Upgrade RxJS to 7 (#129087)

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

examples/search_examples/public/search/app.tsx

@@ -32,6 +32,7 @@ import {
   EuiTabbedContentTab,
 } from '@elastic/eui';
 
+import { lastValueFrom } from 'rxjs';
 import { CoreStart } from '../../../../src/core/public';
 import { mountReactNode } from '../../../../src/core/public/utils';
 import { NavigationPublicPluginStart } from '../../../../src/plugins/navigation/public';
@@ -306,9 +307,9 @@ export const SearchExamplesApp = ({
       const abortController = new AbortController();
       setAbortController(abortController);
       setIsLoading(true);
-      const { rawResponse: res } = await searchSource
+      const { rawResponse: res } = await lastValueFrom(
-        .fetch$({ abortSignal: abortController.signal })
+        searchSource.fetch$({ abortSignal: abortController.signal })
-        .toPromise();
+      );
       setRawResponse(res);
 
       const message = <EuiText>Searched {res.hits.total} documents.</EuiText>;

examples/search_examples/public/search_sessions/app.tsx

@@ -30,7 +30,7 @@ import {
   EuiTitle,
 } from '@elastic/eui';
 import { catchError, map, tap } from 'rxjs/operators';
-import { of } from 'rxjs';
+import { lastValueFrom, of } from 'rxjs';
 
 import { CoreStart } from '../../../../src/core/public';
 import { mountReactNode } from '../../../../src/core/public/utils';
@@ -693,9 +693,8 @@ function doSearch(
   const startTs = performance.now();
 
   // Submit the search request using the `data.search` service.
-  return data.search
+  return lastValueFrom(
-    .search(req, { sessionId })
+    data.search.search(req, { sessionId }).pipe(
-    .pipe(
       tap((res) => {
         if (isCompleteResponse(res)) {
           const avgResult: number | undefined = res.rawResponse.aggregations
@@ -724,7 +723,7 @@ function doSearch(
         return of({ request: req, response: e });
       })
     )
-    .toPromise();
+  );
 }
 
 function getNumeric(fields?: DataViewField[]) {

package.json

@@ -383,7 +383,7 @@
     "redux-actions": "^2.6.5",
     "redux-devtools-extension": "^2.13.8",
     "redux-logger": "^3.0.6",
-    "redux-observable": "^1.2.0",
+    "redux-observable": "2.0.0",
     "redux-saga": "^1.1.3",
     "redux-thunk": "^2.3.0",
     "redux-thunks": "^1.0.0",
@@ -394,7 +394,7 @@
     "reselect": "^4.0.0",
     "resize-observer-polyfill": "^1.5.1",
     "rison-node": "1.0.2",
-    "rxjs": "^6.5.5",
+    "rxjs": "^7.5.5",
     "safe-squel": "^5.12.5",
     "seedrandom": "^3.0.5",
     "semver": "^7.3.2",

packages/elastic-analytics/src/analytics_client/analytics_client.test.ts

@@ -8,7 +8,7 @@
 
 // eslint-disable-next-line max-classes-per-file
 import type { Observable } from 'rxjs';
-import { BehaviorSubject, Subject } from 'rxjs';
+import { BehaviorSubject, lastValueFrom, Subject } from 'rxjs';
 import type { MockedLogger } from '@kbn/logging-mocks';
 import { loggerMock } from '@kbn/logging-mocks';
 import { AnalyticsClient } from './analytics_client';
@@ -113,14 +113,14 @@ describe('AnalyticsClient', () => {
         },
       });
 
+      const internalQueuePromise = lastValueFrom(
         // eslint-disable-next-line dot-notation
-      const internalQueuePromise = analyticsClient['internalEventQueue$']
+        analyticsClient['internalEventQueue$'].pipe(take(3), toArray())
-        .pipe(take(3), toArray())
+      );
-        .toPromise();
 
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3), toArray())
+        analyticsClient.telemetryCounter$.pipe(take(3), toArray())
-        .toPromise();
+      );
 
       analyticsClient.reportEvent('testEvent', { a_field: 'a' });
       analyticsClient.reportEvent('testEvent', { a_field: 'b' });
@@ -259,7 +259,7 @@ describe('AnalyticsClient', () => {
       // Typescript also helps with the config type inference <3
       analyticsClient.registerShipper(MockedShipper, { telemetryCounter$: mockTelemetryCounter$ });
 
-      const counterEventPromise = analyticsClient.telemetryCounter$.pipe(take(1)).toPromise();
+      const counterEventPromise = lastValueFrom(analyticsClient.telemetryCounter$.pipe(take(1)));
 
       const counter: TelemetryCounter = {
         type: TelemetryCounterType.succeeded,
@@ -383,7 +383,7 @@ describe('AnalyticsClient', () => {
         context$,
       });
 
-      const globalContextPromise = globalContext$.pipe(take(2), toArray()).toPromise();
+      const globalContextPromise = lastValueFrom(globalContext$.pipe(take(2), toArray()));
       context$.next({ a_field: true });
       await expect(globalContextPromise).resolves.toEqual([
         {}, // Original empty state
@@ -392,7 +392,7 @@ describe('AnalyticsClient', () => {
     });
 
     test('It does not break if context emits `undefined`', async () => {
-      const context$ = new Subject<{ a_field: boolean }>();
+      const context$ = new Subject<{ a_field: boolean } | undefined | void>();
       analyticsClient.registerContextProvider({
         name: 'contextProviderA',
         schema: {
@@ -406,7 +406,7 @@ describe('AnalyticsClient', () => {
         context$,
       });
 
-      const globalContextPromise = globalContext$.pipe(take(3), toArray()).toPromise();
+      const globalContextPromise = lastValueFrom(globalContext$.pipe(take(3), toArray()));
       context$.next();
       context$.next(undefined);
       await expect(globalContextPromise).resolves.toEqual([
@@ -431,7 +431,7 @@ describe('AnalyticsClient', () => {
         context$,
       });
 
-      const globalContextPromise = globalContext$.pipe(take(1), toArray()).toPromise();
+      const globalContextPromise = lastValueFrom(globalContext$.pipe(take(1), toArray()));
       await expect(globalContextPromise).resolves.toEqual([
         { a_field: true }, // No original empty state
       ]);
@@ -473,7 +473,7 @@ describe('AnalyticsClient', () => {
         context$: contextB$,
       });
 
-      const globalContextPromise = globalContext$.pipe(take(6), toArray()).toPromise();
+      const globalContextPromise = lastValueFrom(globalContext$.pipe(take(6), toArray()));
       contextA$.next({ a_field: true });
       contextB$.next({ b_field: 1 });
       contextB$.next({ a_field: false, b_field: 1 });
@@ -512,7 +512,7 @@ describe('AnalyticsClient', () => {
         context$,
       });
 
-      const globalContextPromise = globalContext$.pipe(take(6), toArray()).toPromise();
+      const globalContextPromise = lastValueFrom(globalContext$.pipe(take(6), toArray()));
       context$.next({ b_field: 1 });
       context$.next({ a_field: false, b_field: 1 });
       context$.next({ a_field: true, b_field: 1 });
@@ -582,7 +582,7 @@ describe('AnalyticsClient', () => {
         context$,
       });
 
-      const globalContextPromise = globalContext$.pipe(take(4), toArray()).toPromise();
+      const globalContextPromise = lastValueFrom(globalContext$.pipe(take(4), toArray()));
       context$.next({ a_field: true });
       // The size of the registry grows on the first emission
       expect(contextProvidersRegistry.size).toBe(1);
@@ -736,11 +736,11 @@ describe('AnalyticsClient', () => {
       // eslint-disable-next-line dot-notation
       const internalEventQueue$ = analyticsClient['internalEventQueue$'];
 
-      const internalQueuePromise = internalEventQueue$.pipe(take(2), toArray()).toPromise();
+      const internalQueuePromise = lastValueFrom(internalEventQueue$.pipe(take(2), toArray()));
 
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(2), toArray())
+        analyticsClient.telemetryCounter$.pipe(take(2), toArray())
-        .toPromise();
+      );
 
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
       analyticsClient.reportEvent('event-type-b', { b_field: 100 });
@@ -781,9 +781,9 @@ describe('AnalyticsClient', () => {
     });
 
     test('Sends events from the internal queue when there are shippers and an opt-in response is true', async () => {
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3 + 2), toArray()) // Waiting for 3 enqueued + 2 batch-shipped events
+        analyticsClient.telemetryCounter$.pipe(take(3 + 2), toArray()) // Waiting for 3 enqueued + 2 batch-shipped events
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the grouping logic as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
@@ -862,9 +862,9 @@ describe('AnalyticsClient', () => {
     });
 
     test('Discards events from the internal queue when there are shippers and an opt-in response is false', async () => {
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3), toArray()) // Waiting for 3 enqueued
+        analyticsClient.telemetryCounter$.pipe(take(3), toArray()) // Waiting for 3 enqueued
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the grouping logic as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
@@ -904,9 +904,9 @@ describe('AnalyticsClient', () => {
     });
 
     test('Discards only one type of the enqueued events based on event_type config', async () => {
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3 + 1), toArray()) // Waiting for 3 enqueued + 1 batch-shipped events
+        analyticsClient.telemetryCounter$.pipe(take(3 + 1), toArray()) // Waiting for 3 enqueued + 1 batch-shipped events
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the grouping logic as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
@@ -965,9 +965,9 @@ describe('AnalyticsClient', () => {
     });
 
     test('Discards the event at the shipper level (for a specific event)', async () => {
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3 + 2), toArray()) // Waiting for 3 enqueued + 2 batch-shipped events
+        analyticsClient.telemetryCounter$.pipe(take(3 + 2), toArray()) // Waiting for 3 enqueued + 2 batch-shipped events
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the grouping logic as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
@@ -1061,9 +1061,9 @@ describe('AnalyticsClient', () => {
     });
 
     test('Discards all the events at the shipper level (globally disabled)', async () => {
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3 + 2), toArray()) // Waiting for 3 enqueued + 2 batch-shipped events
+        analyticsClient.telemetryCounter$.pipe(take(3 + 2), toArray()) // Waiting for 3 enqueued + 2 batch-shipped events
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the grouping logic as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
@@ -1154,9 +1154,9 @@ describe('AnalyticsClient', () => {
       analyticsClient.registerShipper(MockedShipper1, { reportEventsMock });
       analyticsClient.optIn({ global: { enabled: false } });
 
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3), toArray()) // Waiting for 3 enqueued
+        analyticsClient.telemetryCounter$.pipe(take(3), toArray()) // Waiting for 3 enqueued
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the non-grouping logic at this stage as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });
@@ -1197,9 +1197,9 @@ describe('AnalyticsClient', () => {
       analyticsClient.registerShipper(MockedShipper1, { reportEventsMock });
       analyticsClient.optIn({ global: { enabled: true } });
 
-      const telemetryCounterPromise = analyticsClient.telemetryCounter$
+      const telemetryCounterPromise = lastValueFrom(
-        .pipe(take(3 * 2), toArray()) // Waiting for 2 events per each reportEvent call: enqueued and sent_to_shipper
+        analyticsClient.telemetryCounter$.pipe(take(3 * 2), toArray()) // Waiting for 2 events per each reportEvent call: enqueued and sent_to_shipper
-        .toPromise();
+      );
 
       // Send multiple events of 1 type to test the non-grouping logic at this stage as well
       analyticsClient.reportEvent('event-type-a', { a_field: 'a' });

packages/kbn-cli-dev-mode/src/dev_server.ts

@@ -6,8 +6,6 @@
  * Side Public License, v 1.
  */
 
-import { EventEmitter } from 'events';
-
 import * as Rx from 'rxjs';
 import {
   map,
@@ -60,9 +58,9 @@ export class DevServer {
     this.script = options.script;
     this.argv = options.argv;
     this.gracefulTimeout = options.gracefulTimeout;
-    this.processExit$ = options.processExit$ ?? Rx.fromEvent(process as EventEmitter, 'exit');
+    this.processExit$ = options.processExit$ ?? Rx.fromEvent<void>(process, 'exit');
-    this.sigint$ = options.sigint$ ?? Rx.fromEvent(process as EventEmitter, 'SIGINT');
+    this.sigint$ = options.sigint$ ?? Rx.fromEvent<void>(process, 'SIGINT');
-    this.sigterm$ = options.sigterm$ ?? Rx.fromEvent(process as EventEmitter, 'SIGTERM');
+    this.sigterm$ = options.sigterm$ ?? Rx.fromEvent<void>(process, 'SIGTERM');
     this.mapLogLine = options.mapLogLine;
   }
 
@@ -117,7 +115,7 @@ export class DevServer {
    */
   run$ = new Rx.Observable<void>((subscriber) => {
     // listen for SIGINT and forward to process if it's running, otherwise unsub
-    const gracefulShutdown$ = new Rx.Subject();
+    const gracefulShutdown$ = new Rx.Subject<void>();
     subscriber.add(
       this.sigint$
         .pipe(

packages/kbn-cli-dev-mode/src/optimizer.test.ts

@@ -12,7 +12,6 @@ import * as Rx from 'rxjs';
 import { toArray } from 'rxjs/operators';
 import { OptimizerUpdate } from '@kbn/optimizer';
 import { observeLines, createReplaceSerializer } from '@kbn/dev-utils';
-import { firstValueFrom } from '@kbn/std';
 
 import { Optimizer, Options } from './optimizer';
 
@@ -130,7 +129,7 @@ it('uses options to create valid OptimizerConfig', () => {
 
 it('is ready when optimizer phase is success or issue and logs in familiar format', async () => {
   const writeLogTo = new PassThrough();
-  const linesPromise = firstValueFrom(observeLines(writeLogTo).pipe(toArray()));
+  const linesPromise = Rx.firstValueFrom(observeLines(writeLogTo).pipe(toArray()));
 
   const { update$, optimizer } = setup({
     ...defaultOptions,

packages/kbn-cli-dev-mode/src/watcher.test.ts

@@ -10,7 +10,6 @@ import { EventEmitter } from 'events';
 
 import * as Rx from 'rxjs';
 import { materialize, toArray } from 'rxjs/operators';
-import { firstValueFrom } from '@kbn/std';
 
 import { TestLog } from './log';
 import { Watcher, Options } from './watcher';
@@ -112,7 +111,7 @@ it('closes chokidar watcher when unsubscribed', () => {
 
 it('rethrows chokidar errors', async () => {
   const watcher = new Watcher(defaultOptions);
-  const promise = firstValueFrom(watcher.run$.pipe(materialize(), toArray()));
+  const promise = Rx.firstValueFrom(watcher.run$.pipe(materialize(), toArray()));
 
   isMock(mockChokidar);
   mockChokidar.emit('error', new Error('foo bar'));

packages/kbn-config/src/config_service.ts

@@ -9,8 +9,8 @@
 import type { PublicMethodsOf } from '@kbn/utility-types';
 import { Type } from '@kbn/config-schema';
 import { isEqual } from 'lodash';
-import { BehaviorSubject, combineLatest, Observable } from 'rxjs';
+import { BehaviorSubject, combineLatest, firstValueFrom, Observable } from 'rxjs';
-import { distinctUntilChanged, first, map, shareReplay, take, tap } from 'rxjs/operators';
+import { distinctUntilChanged, first, map, shareReplay, tap } from 'rxjs/operators';
 import { Logger, LoggerFactory } from '@kbn/logging';
 
 import { Config, ConfigPath, Env } from '.';
@@ -170,7 +170,7 @@ export class ConfigService {
     const namespace = pathToString(path);
     const hasSchema = this.schemas.has(namespace);
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     if (!hasSchema && config.has(path)) {
       // Throw if there is no schema, but a config exists at the path.
       throw new Error(`No validation schema has been defined for [${namespace}]`);
@@ -195,13 +195,13 @@ export class ConfigService {
   }
 
   public async getUnusedPaths() {
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     const handledPaths = [...this.handledPaths.values()].map(pathToString);
     return config.getFlattenedPaths().filter((path) => !isPathHandled(path, handledPaths));
   }
 
   public async getUsedPaths() {
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     const handledPaths = [...this.handledPaths.values()].map(pathToString);
     return config.getFlattenedPaths().filter((path) => isPathHandled(path, handledPaths));
   }
@@ -211,8 +211,8 @@ export class ConfigService {
   }
 
   private async logDeprecation() {
-    const rawConfig = await this.rawConfigProvider.getConfig$().pipe(take(1)).toPromise();
+    const rawConfig = await firstValueFrom(this.rawConfigProvider.getConfig$());
-    const deprecations = await this.deprecations.pipe(take(1)).toPromise();
+    const deprecations = await firstValueFrom(this.deprecations);
     const deprecationMessages: string[] = [];
     const createAddDeprecation = (domainId: string) => (context: DeprecatedConfigDetails) => {
       if (!context.silent) {

packages/kbn-config/src/raw/raw_config_service.test.ts

@@ -8,7 +8,7 @@
 
 import { mockGetConfigFromFiles } from './raw_config_service.test.mocks';
 
-import { first } from 'rxjs/operators';
+import { firstValueFrom } from 'rxjs';
 import { RawConfigService } from './raw_config_service';
 
 const configFile = '/config/kibana.yml';
@@ -72,7 +72,7 @@ test('returns config at path as observable', async () => {
 
   configService.loadConfig();
 
-  const exampleConfig = await configService.getConfig$().pipe(first()).toPromise();
+  const exampleConfig = await firstValueFrom(configService.getConfig$());
 
   expect(exampleConfig.key).toEqual('value');
   expect(Object.keys(exampleConfig)).toEqual(['key']);

packages/kbn-dev-utils/src/tooling_log/tooling_log.test.ts

@@ -14,6 +14,7 @@ import { Writer } from './writer';
 import { ToolingLogTextWriter } from './tooling_log_text_writer';
 import { ToolingLogCollectingWriter } from './tooling_log_collecting_writer';
 import { createStripAnsiSerializer } from '../serializers/strip_ansi_serializer';
+import { lastValueFrom } from 'rxjs';
 
 expect.addSnapshotSerializer(createStripAnsiSerializer());
 
@@ -146,8 +147,8 @@ describe('#getWritten$()', () => {
     const log = new ToolingLog();
     log.setWriters(writers);
 
-    const done$ = new Rx.Subject();
+    const done$ = new Rx.Subject<void>();
-    const promise = log.getWritten$().pipe(takeUntil(done$), toArray()).toPromise();
+    const promise = lastValueFrom(log.getWritten$().pipe(takeUntil(done$), toArray()));
 
     log.debug('foo');
     log.info('bar');

packages/kbn-optimizer/src/cli.ts

@@ -9,7 +9,7 @@
 import Path from 'path';
 
 import { REPO_ROOT } from '@kbn/utils';
-import { lastValueFrom } from '@kbn/std';
+import { lastValueFrom } from 'rxjs';
 import { run, createFlagError, Flags } from '@kbn/dev-utils';
 
 import { logOptimizerState } from './log_optimizer_state';

packages/kbn-optimizer/src/common/rxjs_helpers.test.ts

@@ -7,8 +7,7 @@
  */
 
 import * as Rx from 'rxjs';
-import { toArray, map } from 'rxjs/operators';
+import { fakeSchedulers } from 'rxjs-marbles/jest';
-import { lastValueFrom } from '@kbn/std';
 
 import { pipeClosure, debounceTimeBuffer, maybeMap, maybe } from './rxjs_helpers';
 
@@ -21,26 +20,26 @@ describe('pipeClosure()', () => {
     const foo$ = Rx.of(1, 2, 3).pipe(
       pipeClosure((source$) => {
         const multiplier = ++counter;
-        return source$.pipe(map((i) => i * multiplier));
+        return source$.pipe(Rx.map((i) => i * multiplier));
       }),
-      toArray()
+      Rx.toArray()
     );
 
-    await expect(lastValueFrom(foo$)).resolves.toMatchInlineSnapshot(`
+    await expect(Rx.lastValueFrom(foo$)).resolves.toMatchInlineSnapshot(`
             Array [
               1,
               2,
               3,
             ]
           `);
-    await expect(lastValueFrom(foo$)).resolves.toMatchInlineSnapshot(`
+    await expect(Rx.lastValueFrom(foo$)).resolves.toMatchInlineSnapshot(`
             Array [
               2,
               4,
               6,
             ]
           `);
-    await expect(lastValueFrom(foo$)).resolves.toMatchInlineSnapshot(`
+    await expect(Rx.lastValueFrom(foo$)).resolves.toMatchInlineSnapshot(`
             Array [
               3,
               6,
@@ -52,9 +51,9 @@ describe('pipeClosure()', () => {
 
 describe('maybe()', () => {
   it('filters out undefined values from the stream', async () => {
-    const foo$ = Rx.of(1, undefined, 2, undefined, 3).pipe(maybe(), toArray());
+    const foo$ = Rx.of(1, undefined, 2, undefined, 3).pipe(maybe(), Rx.toArray());
 
-    await expect(lastValueFrom(foo$)).resolves.toEqual([1, 2, 3]);
+    await expect(Rx.lastValueFrom(foo$)).resolves.toEqual([1, 2, 3]);
   });
 });
 
@@ -62,10 +61,10 @@ describe('maybeMap()', () => {
   it('calls map fn and filters out undefined values returned', async () => {
     const foo$ = Rx.of(1, 2, 3, 4, 5).pipe(
       maybeMap((i) => (i % 2 ? i : undefined)),
-      toArray()
+      Rx.toArray()
     );
 
-    await expect(lastValueFrom(foo$)).resolves.toEqual([1, 3, 5]);
+    await expect(Rx.lastValueFrom(foo$)).resolves.toEqual([1, 3, 5]);
   });
 });
 
@@ -78,31 +77,33 @@ describe('debounceTimeBuffer()', () => {
     jest.useRealTimers();
   });
 
-  it('buffers items until there is n milliseconds of silence, then flushes buffer to stream', async () => {
+  it(
+    'buffers items until there is n milliseconds of silence, then flushes buffer to stream',
+    fakeSchedulers(async (advance) => {
       const foo$ = new Rx.Subject<number>();
       const dest = new Rx.BehaviorSubject<number | undefined>(undefined);
       foo$
         .pipe(
           debounceTimeBuffer(100),
-        map((items) => items.reduce((sum, n) => sum + n))
+          Rx.map((items) => items.reduce((sum, n) => sum + n))
         )
         .subscribe(dest);
 
       foo$.next(1);
       expect(dest.getValue()).toBe(undefined);
 
-    // only wait 99 milliseconds before sending the next value
+      // only wait 50 milliseconds before sending the next value
-    jest.advanceTimersByTime(99);
+      advance(50);
       foo$.next(1);
       expect(dest.getValue()).toBe(undefined);
 
       // only wait 99 milliseconds before sending the next value
-    jest.advanceTimersByTime(99);
+      advance(99);
       foo$.next(1);
       expect(dest.getValue()).toBe(undefined);
 
       // send the next value after 100 milliseconds and observe that it was forwarded
-    jest.advanceTimersByTime(100);
+      advance(500);
       foo$.next(1);
       expect(dest.getValue()).toBe(3);
 
@@ -110,7 +111,8 @@ describe('debounceTimeBuffer()', () => {
       if (!dest.isStopped) {
         throw new Error('Expected destination to stop as soon as the source is completed');
       }
-  });
+    })
+  );
 
   it('clears queue as soon as source completes if source completes before time is up', () => {
     const foo$ = new Rx.Subject<number>();
@@ -118,7 +120,7 @@ describe('debounceTimeBuffer()', () => {
     foo$
       .pipe(
         debounceTimeBuffer(100),
-        map((items) => items.reduce((sum, n) => sum + n))
+        Rx.map((items) => items.reduce((sum, n) => sum + n))
       )
       .subscribe(dest);
 

packages/kbn-optimizer/src/common/rxjs_helpers.ts

@@ -7,8 +7,6 @@
  */
 
 import * as Rx from 'rxjs';
-import { mergeMap, tap, debounceTime, map, toArray } from 'rxjs/operators';
-import { firstValueFrom } from '@kbn/std';
 
 type Operator<T1, T2> = (source: Rx.Observable<T1>) => Rx.Observable<T2>;
 type MapFn<T1, T2> = (item: T1, index: number) => T2;
@@ -29,7 +27,7 @@ export const pipeClosure = <T1, T2>(fn: Operator<T1, T2>): Operator<T1, T2> => {
  * supporting TypeScript
  */
 export const maybe = <T1>(): Operator<T1 | undefined, T1> => {
-  return mergeMap((item) => (item === undefined ? Rx.EMPTY : [item]));
+  return Rx.mergeMap((item) => (item === undefined ? Rx.EMPTY : [item]));
 };
 
 /**
@@ -39,7 +37,7 @@ export const maybe = <T1>(): Operator<T1 | undefined, T1> => {
  * the filter.
  */
 export const maybeMap = <T1, T2>(fn: MapFn<T1, undefined | T2>): Operator<T1, T2> => {
-  return mergeMap((item, index) => {
+  return Rx.mergeMap((item, index) => {
     const result = fn(item, index);
     return result === undefined ? Rx.EMPTY : [result];
   });
@@ -54,9 +52,9 @@ export const debounceTimeBuffer = <T>(ms: number) =>
   pipeClosure((source$: Rx.Observable<T>) => {
     const buffer: T[] = [];
     return source$.pipe(
-      tap((item) => buffer.push(item)),
+      Rx.tap((item) => buffer.push(item)),
-      debounceTime(ms),
+      Rx.debounceTime(ms),
-      map(() => {
+      Rx.map(() => {
         const items = Array.from(buffer);
         buffer.length = 0;
         return items;
@@ -65,4 +63,4 @@ export const debounceTimeBuffer = <T>(ms: number) =>
   });
 
 export const allValuesFrom = <T>(observable: Rx.Observable<T>) =>
-  firstValueFrom(observable.pipe(toArray()));
+  Rx.firstValueFrom(observable.pipe(Rx.toArray()));

packages/kbn-optimizer/src/integration_tests/watch_bundles_for_changes.test.ts

@@ -8,8 +8,8 @@
 
 import * as Rx from 'rxjs';
 import { map } from 'rxjs/operators';
+import { fakeSchedulers } from 'rxjs-marbles/jest';
 import ActualWatchpack from 'watchpack';
-import { lastValueFrom } from '@kbn/std';
 
 import { Bundle, ascending } from '../common';
 import { watchBundlesForChanges$ } from '../optimizer/watch_bundles_for_changes';
@@ -65,10 +65,12 @@ afterEach(async () => {
   jest.useRealTimers();
 });
 
-it('notifies of changes and completes once all bundles have changed', async () => {
+it(
+  'notifies of changes and completes once all bundles have changed',
+  fakeSchedulers(async (advance) => {
     expect.assertions(18);
 
-  const promise = lastValueFrom(
+    const promise = Rx.lastValueFrom(
       watchBundlesForChanges$(bundleCacheEvent$, Date.now()).pipe(
         map((event, i) => {
           // each time we trigger a change event we get a 'changed detected' event
@@ -116,18 +118,19 @@ it('notifies of changes and completes once all bundles have changed', async () =
 
     // foo and bar are changes without 1sec so they are batched
     changeListener(bundleEntryPath(FOO_BUNDLE), 'modified');
-  jest.advanceTimersByTime(900);
+    advance(900);
     changeListener(bundleEntryPath(BAR_BUNDLE), 'modified');
-  jest.advanceTimersByTime(1000);
+    advance(1000);
 
     // baz is the only change in 1sec so it is on its own
     changeListener(bundleEntryPath(BAZ_BUNDLE), 'modified');
-  jest.advanceTimersByTime(1000);
+    advance(1000);
 
     // finish by changing box and car
     changeListener(bundleEntryPath(BOX_BUNDLE), 'deleted');
     changeListener(bundleEntryPath(CAR_BUNDLE), 'deleted');
-  jest.advanceTimersByTime(1000);
+    advance(1000);
 
     await expect(promise).resolves.toEqual(undefined);
-});
+  })
+);

packages/kbn-optimizer/src/optimizer/observe_worker.ts

@@ -159,7 +159,7 @@ export function observeWorker(
     let lastMsg: WorkerMsg;
     const worker$: Rx.Observable<WorkerMsg | WorkerStatus> = Rx.merge(
       Rx.of({
-        type: 'worker started',
+        type: 'worker started' as const,
         bundles,
       }),
       // TypeScript note: As long as the proc stdio[1] is 'pipe', then stdout will not be null

packages/kbn-optimizer/src/worker/run_compilers.ts

@@ -27,7 +27,7 @@ const observeCompiler = (
   compiler: webpack.Compiler
 ): Rx.Observable<CompilerMsg> => {
   const compilerMsgs = new CompilerMsgs(bundle.id);
-  const done$ = new Rx.Subject();
+  const done$ = new Rx.Subject<void>();
   const { beforeRun, watchRun, done } = compiler.hooks;
 
   /**

packages/kbn-pm/src/utils/watch.ts

@@ -87,8 +87,8 @@ export function waitUntilWatchIsReady(stream: NodeJS.EventEmitter, opts: IWatchO
   stream.once('error', onErrorListener);
   stream.on('data', onDataListener);
 
-  return Rx.race(getWatchHandlers(buildOutput$, opts))
+  return Rx.firstValueFrom(
-    .pipe(
+    Rx.race(getWatchHandlers(buildOutput$, opts)).pipe(
       mergeMap((whenReady) => whenReady),
       finalize(() => {
         stream.removeListener('data', onDataListener);
@@ -98,5 +98,5 @@ export function waitUntilWatchIsReady(stream: NodeJS.EventEmitter, opts: IWatchO
         buildOutput$.complete();
       })
     )
-    .toPromise();
+  );
 }

packages/kbn-shared-ux-components/src/exit_full_screen_button/__snapshots__/exit_full_screen_button.test.tsx.snap

@@ -4,9 +4,7 @@ exports[`<ExitFullScreenButton /> is rendered 1`] = `
 <SharedUxServicesProvider
   application={
     Object {
-      "currentAppId$": Observable {
+      "currentAppId$": Observable {},
-        "_isScalar": false,
-      },
       "navigateToUrl": [Function],
     }
   }

packages/kbn-shared-ux-components/src/page_template/no_data_page/no_data_card/__snapshots__/elastic_agent_card.component.test.tsx.snap

@@ -4,10 +4,9 @@ exports[`ElasticAgentCardComponent props button 1`] = `
 <RedirectAppLinks
   currentAppId$={
     Observable {
-      "_isScalar": false,
       "source": Subject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "hasError": false,
         "isStopped": false,
         "observers": Array [],
@@ -30,10 +29,9 @@ exports[`ElasticAgentCardComponent props href 1`] = `
 <RedirectAppLinks
   currentAppId$={
     Observable {
-      "_isScalar": false,
       "source": Subject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "hasError": false,
         "isStopped": false,
         "observers": Array [],
@@ -56,10 +54,9 @@ exports[`ElasticAgentCardComponent renders 1`] = `
 <RedirectAppLinks
   currentAppId$={
     Observable {
-      "_isScalar": false,
       "source": Subject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "hasError": false,
         "isStopped": false,
         "observers": Array [],
@@ -81,10 +78,9 @@ exports[`ElasticAgentCardComponent renders with canAccessFleet false 1`] = `
 <RedirectAppLinks
   currentAppId$={
     Observable {
-      "_isScalar": false,
       "source": Subject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "hasError": false,
         "isStopped": false,
         "observers": Array [],

packages/kbn-shared-ux-components/src/page_template/no_data_page/no_data_card/__snapshots__/elastic_agent_card.test.tsx.snap

@@ -4,9 +4,7 @@ exports[`ElasticAgentCard renders 1`] = `
 <SharedUxServicesProvider
   application={
     Object {
-      "currentAppId$": Observable {
+      "currentAppId$": Observable {},
-        "_isScalar": false,
-      },
       "navigateToUrl": [Function],
     }
   }
@@ -142,20 +140,12 @@ exports[`ElasticAgentCard renders 1`] = `
   <ElasticAgentCard>
     <ElasticAgentCardComponent
       canAccessFleet={true}
-      currentAppId$={
+      currentAppId$={Observable {}}
-        Observable {
-          "_isScalar": false,
-        }
-      }
       href="/app/integrations/browse"
       navigateToUrl={[Function]}
     >
       <RedirectAppLinks
-        currentAppId$={
+        currentAppId$={Observable {}}
-          Observable {
-            "_isScalar": false,
-          }
-        }
         navigateToUrl={[Function]}
       >
         <div>

packages/kbn-shared-ux-components/src/toolbar/buttons/icon_button_group/__snapshots__/icon_button_group.test.tsx.snap

@@ -4,9 +4,7 @@ exports[`<IconButtonGroup /> is rendered 1`] = `
 <SharedUxServicesProvider
   application={
     Object {
-      "currentAppId$": Observable {
+      "currentAppId$": Observable {},
-        "_isScalar": false,
-      },
       "navigateToUrl": [Function],
     }
   }

packages/kbn-shared-ux-components/src/toolbar/buttons/primary/__snapshots__/primary.test.tsx.snap

@@ -4,9 +4,7 @@ exports[`<ToolbarButton /> is rendered 1`] = `
 <SharedUxServicesProvider
   application={
     Object {
-      "currentAppId$": Observable {
+      "currentAppId$": Observable {},
-        "_isScalar": false,
-      },
       "navigateToUrl": [Function],
     }
   }

packages/kbn-std/src/index.ts

@@ -19,7 +19,6 @@ export { isRelativeUrl, modifyUrl, getUrlOrigin } from './url';
 export { unset } from './unset';
 export { getFlattenedObject } from './get_flattened_object';
 export { ensureNoUnsafeProperties } from './ensure_no_unsafe_properties';
-export * from './rxjs_7';
 export {
   map$,
   mapWithLimit$,

packages/kbn-std/src/iteration/for_each.ts

@@ -6,9 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { defaultIfEmpty } from 'rxjs/operators';
+import { lastValueFrom, defaultIfEmpty } from 'rxjs';
-
-import { lastValueFrom } from '../rxjs_7';
 import { mapWithLimit$ } from './observable';
 import { IterableInput, AsyncMapFn } from './types';
 
@@ -21,7 +19,7 @@ import { IterableInput, AsyncMapFn } from './types';
  * @param fn Function to call for each item
  */
 export async function asyncForEach<T>(iterable: IterableInput<T>, fn: AsyncMapFn<T, any>) {
-  await lastValueFrom(mapWithLimit$(iterable, Infinity, fn).pipe(defaultIfEmpty()));
+  await lastValueFrom(mapWithLimit$(iterable, Infinity, fn).pipe(defaultIfEmpty(undefined)));
 }
 
 /**
@@ -40,5 +38,5 @@ export async function asyncForEachWithLimit<T>(
   limit: number,
   fn: AsyncMapFn<T, any>
 ) {
-  await lastValueFrom(mapWithLimit$(iterable, limit, fn).pipe(defaultIfEmpty()));
+  await lastValueFrom(mapWithLimit$(iterable, limit, fn).pipe(defaultIfEmpty(undefined)));
 }

packages/kbn-std/src/iteration/map.ts

@@ -6,9 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { from } from 'rxjs';
+import { from, lastValueFrom } from 'rxjs';
 import { toArray } from 'rxjs/operators';
-import { lastValueFrom } from '../rxjs_7';
 
 import { IterableInput, AsyncMapFn, AsyncMapResult } from './types';
 import { mapWithLimit$ } from './observable';

packages/kbn-std/src/iteration/observable.test.ts

@@ -8,7 +8,6 @@
 
 import * as Rx from 'rxjs';
 import { toArray } from 'rxjs/operators';
-import { lastValueFrom } from '../rxjs_7';
 
 import { map$, mapWithLimit$ } from './observable';
 import { list, sleep, generator } from './test_helpers';
@@ -23,7 +22,7 @@ describe('mapWithLimit$', () => {
     let active = 0;
     const limit = Math.random() > 0.5 ? 20 : 40;
 
-    const results = await lastValueFrom(
+    const results = await Rx.lastValueFrom(
       mapWithLimit$(list(100), limit, async (n) => {
         active += 1;
         if (active > maxConcurrency) {
@@ -50,7 +49,7 @@ describe('mapWithLimit$', () => {
     ['observable', Rx.of(1, 2, 3, 4, 5), [1, 2, 3, 4, 5]] as const,
   ])('works with %p', async (_, iter, expected) => {
     const mock = jest.fn(async (n) => n);
-    const results = await lastValueFrom(mapWithLimit$(iter, 1, mock).pipe(toArray()));
+    const results = await Rx.lastValueFrom(mapWithLimit$(iter, 1, mock).pipe(toArray()));
     expect(results).toEqual(expected);
   });
 });
@@ -60,7 +59,7 @@ describe('map$', () => {
     let maxConcurrency = 0;
     let active = 0;
 
-    const results = await lastValueFrom(
+    const results = await Rx.lastValueFrom(
       map$(list(100), async (n) => {
         active += 1;
         if (active > maxConcurrency) {

packages/kbn-std/src/iteration/types.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { Subscribable } from 'rxjs';
+import { ObservableInput } from 'rxjs';
 
-export type IterableInput<T> = Iterable<T> | Subscribable<T>;
+export type IterableInput<T> = Iterable<T> | ObservableInput<T>;
-export type AsyncMapResult<T> = Promise<T> | Subscribable<T>;
+export type AsyncMapResult<T> = Promise<T> | ObservableInput<T>;
 export type AsyncMapFn<T1, T2> = (item: T1, i: number) => AsyncMapResult<T2>;

packages/kbn-std/src/rxjs_7.test.ts

@@ -1,82 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License
- * 2.0 and the Server Side Public License, v 1; you may not use this file except
- * in compliance with, at your election, the Elastic License 2.0 or the Server
- * Side Public License, v 1.
- */
-
-import * as Rx from 'rxjs';
-
-import { firstValueFrom, lastValueFrom } from './rxjs_7';
-
-// create an empty observable that completes with no notifications
-// after a delay to ensure helpers aren't checking for the EMPTY constant
-function empty() {
-  return new Rx.Observable<never>((subscriber) => {
-    setTimeout(() => {
-      subscriber.complete();
-    }, 0);
-  });
-}
-
-describe('firstValueFrom()', () => {
-  it('resolves to the first value from the observable', async () => {
-    await expect(firstValueFrom(Rx.of(1, 2, 3))).resolves.toBe(1);
-  });
-
-  it('rejects if the observable is empty', async () => {
-    await expect(firstValueFrom(empty())).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"no elements in sequence"`
-    );
-  });
-
-  it('unsubscribes from a source observable that emits synchronously', async () => {
-    const values = [1, 2, 3, 4];
-    let unsubscribed = false;
-    const source = new Rx.Observable<number>((subscriber) => {
-      while (!subscriber.closed && values.length) {
-        subscriber.next(values.shift()!);
-      }
-      unsubscribed = subscriber.closed;
-      subscriber.complete();
-    });
-
-    await expect(firstValueFrom(source)).resolves.toMatchInlineSnapshot(`1`);
-    if (!unsubscribed) {
-      throw new Error('expected source to be unsubscribed');
-    }
-    expect(values).toEqual([2, 3, 4]);
-  });
-
-  it('unsubscribes from the source observable after first async notification', async () => {
-    const values = [1, 2, 3, 4];
-    let unsubscribed = false;
-    const source = new Rx.Observable<number>((subscriber) => {
-      setTimeout(() => {
-        while (!subscriber.closed) {
-          subscriber.next(values.shift()!);
-        }
-        unsubscribed = subscriber.closed;
-      });
-    });
-
-    await expect(firstValueFrom(source)).resolves.toMatchInlineSnapshot(`1`);
-    if (!unsubscribed) {
-      throw new Error('expected source to be unsubscribed');
-    }
-    expect(values).toEqual([2, 3, 4]);
-  });
-});
-
-describe('lastValueFrom()', () => {
-  it('resolves to the last value from the observable', async () => {
-    await expect(lastValueFrom(Rx.of(1, 2, 3))).resolves.toBe(3);
-  });
-
-  it('rejects if the observable is empty', async () => {
-    await expect(lastValueFrom(empty())).rejects.toThrowErrorMatchingInlineSnapshot(
-      `"no elements in sequence"`
-    );
-  });
-});

packages/kbn-std/src/rxjs_7.ts

@@ -1,19 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License
- * 2.0 and the Server Side Public License, v 1; you may not use this file except
- * in compliance with, at your election, the Elastic License 2.0 or the Server
- * Side Public License, v 1.
- */
-
-import { Observable } from 'rxjs';
-import { first, last } from 'rxjs/operators';
-
-export function firstValueFrom<T>(source: Observable<T>) {
-  // we can't use SafeSubscriber the same way that RxJS 7 does, so instead we
-  return source.pipe(first()).toPromise();
-}
-
-export function lastValueFrom<T>(source: Observable<T>) {
-  return source.pipe(last()).toPromise();
-}

packages/kbn-test/src/kbn_client/kbn_client_saved_objects.ts

@@ -10,7 +10,6 @@ import { inspect } from 'util';
 
 import * as Rx from 'rxjs';
 import { mergeMap } from 'rxjs/operators';
-import { lastValueFrom } from '@kbn/std';
 import { ToolingLog, isAxiosResponseError, createFailError } from '@kbn/dev-utils';
 
 import { KbnClientRequester, uriencode } from './kbn_client_requester';
@@ -83,7 +82,7 @@ interface DeleteObjectsOptions {
 
 async function concurrently<T>(maxConcurrency: number, arr: T[], fn: (item: T) => Promise<void>) {
   if (arr.length) {
-    await lastValueFrom(
+    await Rx.lastValueFrom(
       Rx.from(arr).pipe(mergeMap(async (item) => await fn(item), maxConcurrency))
     );
   }

src/cli/serve/integration_tests/reload_logging_config.test.ts

@@ -117,7 +117,7 @@ describe.skip('Server logging configuration', function () {
           )
           .toPromise();
 
-        const lastMessage = await message$.pipe(take(1)).toPromise();
+        const lastMessage = await Rx.firstValueFrom(message$);
         expect(containsJsonOnly(lastMessage)).toBe(true);
 
         createConfigManager(configFilePath).modify((oldConfig) => {

src/core/public/application/__snapshots__/application_service.test.ts.snap

@@ -4,15 +4,15 @@ exports[`#start() getComponent returns renderable JSX tree 1`] = `
 <AppRouter
   appStatuses$={
     AnonymousSubject {
-      "_isScalar": false,
       "closed": false,
+      "currentObservers": null,
       "destination": AnonymousSubject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "destination": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": Array [],
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -21,14 +21,11 @@ exports[`#start() getComponent returns renderable JSX tree 1`] = `
         "hasError": false,
         "isStopped": false,
         "observers": Array [],
-        "operator": MapOperator {
+        "operator": [Function],
-          "project": [Function],
-          "thisArg": undefined,
-        },
         "source": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": Array [],
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -41,12 +38,12 @@ exports[`#start() getComponent returns renderable JSX tree 1`] = `
       "observers": Array [],
       "operator": [Function],
       "source": AnonymousSubject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "destination": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": Array [],
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -55,14 +52,11 @@ exports[`#start() getComponent returns renderable JSX tree 1`] = `
         "hasError": false,
         "isStopped": false,
         "observers": Array [],
-        "operator": MapOperator {
+        "operator": [Function],
-          "project": [Function],
-          "thisArg": undefined,
-        },
         "source": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": Array [],
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -85,7 +79,6 @@ exports[`#start() getComponent returns renderable JSX tree 1`] = `
   setIsMounting={[Function]}
   theme$={
     Observable {
-      "_isScalar": false,
       "_subscribe": [Function],
     }
   }

src/core/public/application/application_service.test.ts

@@ -13,8 +13,8 @@ import {
 } from './application_service.test.mocks';
 
 import { createElement } from 'react';
-import { BehaviorSubject, Subject } from 'rxjs';
+import { BehaviorSubject, firstValueFrom, Subject } from 'rxjs';
-import { bufferCount, take, takeUntil } from 'rxjs/operators';
+import { bufferCount, takeUntil } from 'rxjs/operators';
 import { mount, shallow } from 'enzyme';
 
 import { httpServiceMock } from '../http/http_service.mock';
@@ -96,7 +96,7 @@ describe('#setup()', () => {
       );
       const { applications$ } = await service.start(startDeps);
 
-      let applications = await applications$.pipe(take(1)).toPromise();
+      let applications = await firstValueFrom(applications$);
       expect(applications.size).toEqual(2);
       expect(applications.get('app1')).toEqual(
         expect.objectContaining({
@@ -125,7 +125,7 @@ describe('#setup()', () => {
         deepLinks: [{ id: 'subapp2', title: 'Subapp 2', path: '/subapp2' }],
       }));
 
-      applications = await applications$.pipe(take(1)).toPromise();
+      applications = await firstValueFrom(applications$);
       expect(applications.size).toEqual(2);
       expect(applications.get('app1')).toEqual(
         expect.objectContaining({
@@ -205,7 +205,7 @@ describe('#setup()', () => {
         })
       );
       const start = await service.start(startDeps);
-      const applications = await start.applications$.pipe(take(1)).toPromise();
+      const applications = await firstValueFrom(start.applications$);
 
       expect(applications.size).toEqual(2);
       expect(applications.get('app1')).toEqual(
@@ -252,7 +252,7 @@ describe('#setup()', () => {
       );
 
       const { applications$ } = await service.start(startDeps);
-      const applications = await applications$.pipe(take(1)).toPromise();
+      const applications = await firstValueFrom(applications$);
 
       expect(applications.size).toEqual(2);
       expect(applications.get('app1')).toEqual(
@@ -295,7 +295,7 @@ describe('#setup()', () => {
       );
 
       const start = await service.start(startDeps);
-      const applications = await start.applications$.pipe(take(1)).toPromise();
+      const applications = await firstValueFrom(start.applications$);
 
       expect(applications.size).toEqual(1);
       expect(applications.get('app1')).toEqual(
@@ -410,7 +410,7 @@ describe('#setup()', () => {
 
       updater$.next((app) => ({ defaultPath: '/foo' }));
 
-      let appInfos = await applications$.pipe(take(1)).toPromise();
+      let appInfos = await firstValueFrom(applications$);
 
       expect(appInfos.get('app1')!.deepLinks).toEqual([
         {
@@ -445,7 +445,7 @@ describe('#setup()', () => {
         ],
       }));
 
-      appInfos = await applications$.pipe(take(1)).toPromise();
+      appInfos = await firstValueFrom(applications$);
 
       expect(appInfos.get('app1')!.deepLinks).toEqual([
         {
@@ -496,7 +496,7 @@ describe('#start()', () => {
     register(Symbol(), createApp({ id: 'app2' }));
 
     const { applications$ } = await service.start(startDeps);
-    const availableApps = await applications$.pipe(take(1)).toPromise();
+    const availableApps = await firstValueFrom(applications$);
 
     expect(availableApps.size).toEqual(2);
     expect([...availableApps.keys()]).toEqual(['app1', 'app2']);
@@ -548,7 +548,7 @@ describe('#start()', () => {
     register(Symbol(), createApp({ id: 'app2' }));
 
     const { applications$ } = await service.start(startDeps);
-    const availableApps = await applications$.pipe(take(1)).toPromise();
+    const availableApps = await firstValueFrom(applications$);
 
     expect([...availableApps.keys()]).toEqual(['app1']);
   });
@@ -802,7 +802,7 @@ describe('#start()', () => {
       service.setup(setupDeps);
 
       const { currentAppId$, navigateToApp } = await service.start(startDeps);
-      const stop$ = new Subject();
+      const stop$ = new Subject<void>();
       const promise = currentAppId$.pipe(bufferCount(4), takeUntil(stop$)).toPromise();
 
       await navigateToApp('alpha');
@@ -827,7 +827,7 @@ describe('#start()', () => {
       service.setup(setupDeps);
 
       const { currentAppId$, navigateToApp } = await service.start(startDeps);
-      const stop$ = new Subject();
+      const stop$ = new Subject<void>();
       const promise = currentAppId$.pipe(bufferCount(4), takeUntil(stop$)).toPromise();
 
       await navigateToApp('delta', { openInNewTab: true });
@@ -871,7 +871,7 @@ describe('#start()', () => {
 
       const { navigateToApp, getComponent } = await service.start(startDeps);
       const httpLoadingCount$ = startDeps.http.addLoadingCountSource.mock.calls[0][0];
-      const stop$ = new Subject();
+      const stop$ = new Subject<void>();
       const currentLoadingCount$ = new BehaviorSubject(0);
       httpLoadingCount$.pipe(takeUntil(stop$)).subscribe(currentLoadingCount$);
       const loadingPromise = httpLoadingCount$.pipe(bufferCount(5), takeUntil(stop$)).toPromise();

src/core/public/application/application_service.tsx

@@ -7,7 +7,7 @@
  */
 
 import React from 'react';
-import { BehaviorSubject, Observable, Subject, Subscription } from 'rxjs';
+import { BehaviorSubject, firstValueFrom, Observable, Subject, Subscription } from 'rxjs';
 import { map, shareReplay, takeUntil, distinctUntilChanged, filter, take } from 'rxjs/operators';
 import { createBrowserHistory, History } from 'history';
 
@@ -99,7 +99,7 @@ export class ApplicationService {
   private currentActionMenu$ = new BehaviorSubject<MountPoint | undefined>(undefined);
   private readonly statusUpdaters$ = new BehaviorSubject<Map<symbol, AppUpdaterWrapper>>(new Map());
   private readonly subscriptions: Subscription[] = [];
-  private stop$ = new Subject();
+  private stop$ = new Subject<void>();
   private registrationClosed = false;
   private history?: History<any>;
   private navigate?: (url: string, state: unknown, replace: boolean) => void;
@@ -120,7 +120,7 @@ export class ApplicationService {
       createBrowserHistory({
         basename,
         getUserConfirmation: getUserConfirmationHandler({
-          overlayPromise: this.overlayStart$.pipe(take(1)).toPromise(),
+          overlayPromise: firstValueFrom(this.overlayStart$.pipe(take(1))),
         }),
       });
 

src/core/public/chrome/chrome_service.test.ts

@@ -9,7 +9,7 @@
 import { shallow } from 'enzyme';
 import React from 'react';
 import * as Rx from 'rxjs';
-import { take, toArray } from 'rxjs/operators';
+import { toArray } from 'rxjs/operators';
 import { App, PublicAppInfo } from '../application';
 import { applicationServiceMock } from '../application/application_service.mock';
 import { docLinksServiceMock } from '../doc_links/doc_links_service.mock';
@@ -229,7 +229,7 @@ describe('start', () => {
       const { chrome, service } = await start({ startDeps });
       const promise = chrome.getIsVisible$().pipe(toArray()).toPromise();
 
-      const availableApps = await applications$.pipe(take(1)).toPromise();
+      const availableApps = await Rx.firstValueFrom(applications$);
       [...availableApps.keys()].forEach((appId) => navigateToApp(appId));
       service.stop();
 

src/core/public/chrome/chrome_service.tsx

@@ -55,7 +55,7 @@ export interface StartDeps {
 export class ChromeService {
   private isVisible$!: Observable<boolean>;
   private isForceHidden$!: BehaviorSubject<boolean>;
-  private readonly stop$ = new ReplaySubject(1);
+  private readonly stop$ = new ReplaySubject<void>(1);
   private readonly navControls = new NavControlsService();
   private readonly navLinks = new NavLinksService();
   private readonly recentlyAccessed = new RecentlyAccessedService();

src/core/public/chrome/nav_controls/nav_controls_service.ts

@@ -50,7 +50,7 @@ export interface ChromeNavControls {
 
 /** @internal */
 export class NavControlsService {
-  private readonly stop$ = new ReplaySubject(1);
+  private readonly stop$ = new ReplaySubject<void>(1);
 
   public start() {
     const navControlsLeft$ = new BehaviorSubject<ReadonlySet<ChromeNavControl>>(new Set());

src/core/public/chrome/nav_links/nav_links_service.ts

@@ -69,7 +69,7 @@ export interface ChromeNavLinks {
 }
 
 export class NavLinksService {
-  private readonly stop$ = new ReplaySubject(1);
+  private readonly stop$ = new ReplaySubject<void>(1);
 
   public start({ application, http }: StartDeps): ChromeNavLinks {
     const navLinks$ = new BehaviorSubject<ReadonlyMap<string, NavLinkWrapper>>(new Map());

src/core/public/chrome/recently_accessed/recently_accessed_service.test.ts

@@ -90,7 +90,7 @@ describe('RecentlyAccessed#start()', () => {
 
   it('exposes an observable', async () => {
     const { recentlyAccessed } = await getStart();
-    const stop$ = new Subject();
+    const stop$ = new Subject<void>();
     const observedValues$ = recentlyAccessed
       .get$()
       .pipe(bufferCount(3), takeUntil(stop$))

src/core/public/chrome/ui/header/__snapshots__/collapsible_nav.test.tsx.snap

@@ -4,48 +4,32 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
 <CollapsibleNav
   appId$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": "test",
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -65,7 +49,6 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
   closeNav={[Function]}
   customNavLink$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Object {
         "baseUrl": "/",
         "category": undefined,
@@ -77,45 +60,30 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
         "url": "/",
       },
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -127,7 +95,6 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
   isNavOpen={true}
   navLinks$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Array [
         Object {
           "baseUrl": "/",
@@ -246,45 +213,30 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
         },
       ],
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -295,7 +247,6 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
   onIsLockedUpdate={[Function]}
   recentlyAccessed$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Array [
         Object {
           "id": "recent 1",
@@ -309,45 +260,30 @@ exports[`CollapsibleNav renders links grouped by category 1`] = `
         },
       ],
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2073,48 +2009,32 @@ exports[`CollapsibleNav renders the default nav 1`] = `
 <CollapsibleNav
   appId$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": "test",
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2134,48 +2054,32 @@ exports[`CollapsibleNav renders the default nav 1`] = `
   closeNav={[Function]}
   customNavLink$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": undefined,
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2187,48 +2091,32 @@ exports[`CollapsibleNav renders the default nav 1`] = `
   isNavOpen={false}
   navLinks$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Array [],
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2239,48 +2127,32 @@ exports[`CollapsibleNav renders the default nav 1`] = `
   onIsLockedUpdate={[Function]}
   recentlyAccessed$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Array [],
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2321,48 +2193,32 @@ exports[`CollapsibleNav renders the default nav 2`] = `
 <CollapsibleNav
   appId$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": "test",
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2382,48 +2238,32 @@ exports[`CollapsibleNav renders the default nav 2`] = `
   closeNav={[Function]}
   customNavLink$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": undefined,
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2436,48 +2276,32 @@ exports[`CollapsibleNav renders the default nav 2`] = `
   isOpen={true}
   navLinks$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Array [],
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,
@@ -2488,48 +2312,32 @@ exports[`CollapsibleNav renders the default nav 2`] = `
   onIsLockedUpdate={[Function]}
   recentlyAccessed$={
     BehaviorSubject {
-      "_isScalar": false,
       "_value": Array [],
       "closed": false,
+      "currentObservers": null,
       "hasError": false,
       "isStopped": false,
       "observers": Array [
-        Subscriber {
+        SafeSubscriber {
-          "_parentOrParents": null,
+          "_finalizers": Array [
-          "_subscriptions": Array [
+            Subscription {
-            SubjectSubscription {
+              "_finalizers": null,
-              "_parentOrParents": [Circular],
+              "_parentage": [Circular],
-              "_subscriptions": null,
               "closed": false,
-              "subject": [Circular],
+              "initialTeardown": [Function],
-              "subscriber": [Circular],
             },
           ],
+          "_parentage": null,
           "closed": false,
-          "destination": SafeSubscriber {
+          "destination": ConsumerObserver {
-            "_complete": undefined,
+            "partialObserver": Object {
-            "_context": [Circular],
+              "complete": undefined,
-            "_error": undefined,
+              "error": undefined,
-            "_next": [Function],
-            "_parentOrParents": null,
-            "_parentSubscriber": [Circular],
-            "_subscriptions": null,
-            "closed": false,
-            "destination": Object {
-              "closed": true,
-              "complete": [Function],
-              "error": [Function],
               "next": [Function],
             },
-            "isStopped": false,
-            "syncErrorThrowable": false,
-            "syncErrorThrown": false,
-            "syncErrorValue": null,
           },
+          "initialTeardown": undefined,
           "isStopped": false,
-          "syncErrorThrowable": true,
-          "syncErrorThrown": false,
-          "syncErrorValue": null,
         },
       ],
       "thrownError": null,

src/core/public/http/loading_count_service.ts

@@ -34,7 +34,7 @@ export type LoadingCountStart = LoadingCountSetup;
 
 /** @internal */
 export class LoadingCountService implements CoreService<LoadingCountSetup, LoadingCountStart> {
-  private readonly stop$ = new Subject();
+  private readonly stop$ = new Subject<void>();
   private readonly loadingCount$ = new BehaviorSubject(0);
 
   public setup({ fatalErrors }: { fatalErrors: FatalErrorsSetup }) {

src/core/public/notifications/toasts/__snapshots__/toasts_service.test.tsx.snap

@@ -12,7 +12,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -22,11 +21,10 @@ Array [
         dismissToast={[Function]}
         toasts$={
           Observable {
-            "_isScalar": false,
             "source": BehaviorSubject {
-              "_isScalar": false,
               "_value": Array [],
               "closed": false,
+              "currentObservers": null,
               "hasError": false,
               "isStopped": false,
               "observers": Array [],

src/core/public/notifications/toasts/toasts_api.test.ts

@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { take } from 'rxjs/operators';
+import { firstValueFrom } from 'rxjs';
 
 import { ToastsApi } from './toasts_api';
 
@@ -14,7 +14,7 @@ import { uiSettingsServiceMock } from '../../ui_settings/ui_settings_service.moc
 import { i18nServiceMock } from '../../i18n/i18n_service.mock';
 
 async function getCurrentToasts(toasts: ToastsApi) {
-  return await toasts.get$().pipe(take(1)).toPromise();
+  return await firstValueFrom(toasts.get$());
 }
 
 function uiSettingsMock() {

src/core/public/overlays/flyout/__snapshots__/flyout_service.test.tsx.snap

@@ -20,7 +20,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -56,7 +55,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -81,7 +79,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -103,7 +100,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -132,7 +128,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -157,7 +152,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -179,7 +173,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }

src/core/public/overlays/modal/__snapshots__/modal_service.test.tsx.snap

@@ -22,7 +22,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -47,7 +46,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -69,7 +67,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -108,7 +105,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -131,7 +127,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -159,7 +154,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -180,7 +174,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -205,7 +198,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -241,7 +233,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -264,7 +255,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -290,7 +280,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -315,7 +304,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -336,7 +324,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -360,7 +347,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -382,7 +368,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -411,7 +396,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -434,7 +418,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -460,7 +443,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -485,7 +467,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -506,7 +487,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -530,7 +510,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -552,7 +531,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -586,7 +564,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -609,7 +586,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -635,7 +611,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -660,7 +635,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -681,7 +655,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -705,7 +678,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -727,7 +699,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -756,7 +727,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -779,7 +749,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -805,7 +774,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -830,7 +798,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -851,7 +818,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -875,7 +841,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -897,7 +862,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -929,7 +893,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -965,7 +928,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -990,7 +952,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -1012,7 +973,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -1041,7 +1001,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -1066,7 +1025,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -1088,7 +1046,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -1122,7 +1079,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -1147,7 +1103,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -1169,7 +1124,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }
@@ -1198,7 +1152,6 @@ Array [
                     globalStyles={false}
                     theme$={
                       Observable {
-                        "_isScalar": false,
                         "_subscribe": [Function],
                       }
                     }
@@ -1223,7 +1176,6 @@ Array [
                   globalStyles={false}
                   theme$={
                     Observable {
-                      "_isScalar": false,
                       "_subscribe": [Function],
                     }
                   }
@@ -1245,7 +1197,6 @@ Array [
       theme={
         Object {
           "theme$": Observable {
-            "_isScalar": false,
             "_subscribe": [Function],
           },
         }

src/core/public/plugins/plugin.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { Subject } from 'rxjs';
+import { firstValueFrom, Subject } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { DiscoveredPlugin, PluginOpaqueId } from '../../server';
 import { PluginInitializerContext } from './plugin_context';
 import { read } from './plugin_reader';
@@ -61,7 +60,7 @@ export class PluginWrapper<
   private instance?: Plugin<TSetup, TStart, TPluginsSetup, TPluginsStart>;
 
   private readonly startDependencies$ = new Subject<[CoreStart, TPluginsStart, TStart]>();
-  public readonly startDependencies = this.startDependencies$.pipe(first()).toPromise();
+  public readonly startDependencies = firstValueFrom(this.startDependencies$);
 
   constructor(
     public readonly discoveredPlugin: DiscoveredPlugin,

src/core/public/theme/theme_service.ts

@@ -17,7 +17,7 @@ export interface SetupDeps {
 
 export class ThemeService {
   private theme$?: Observable<CoreTheme>;
-  private stop$ = new Subject();
+  private stop$ = new Subject<void>();
 
   public setup({ injectedMetadata }: SetupDeps): ThemeServiceSetup {
     const theme = injectedMetadata.getTheme();

src/core/public/ui_settings/ui_settings_api.test.ts

@@ -169,7 +169,7 @@ describe('#getLoadingCount$()', () => {
     });
 
     const { uiSettingsApi } = setup();
-    const done$ = new Rx.Subject();
+    const done$ = new Rx.Subject<void>();
     const promise = uiSettingsApi.getLoadingCount$().pipe(takeUntil(done$), toArray()).toPromise();
 
     await uiSettingsApi.batchSet('foo', 'bar');
@@ -194,7 +194,7 @@ describe('#getLoadingCount$()', () => {
     );
 
     const { uiSettingsApi } = setup();
-    const done$ = new Rx.Subject();
+    const done$ = new Rx.Subject<void>();
     const promise = uiSettingsApi.getLoadingCount$().pipe(takeUntil(done$), toArray()).toPromise();
 
     await uiSettingsApi.batchSet('foo', 'bar');

src/core/public/ui_settings/ui_settings_service.test.ts

@@ -34,7 +34,10 @@ describe('#stop', () => {
     service.stop();
 
     await expect(
-      Rx.combineLatest(client.getUpdate$(), client.getUpdateErrors$(), loadingCount$!).toPromise()
+      Rx.lastValueFrom(
+        Rx.combineLatest([client.getUpdate$(), client.getUpdateErrors$(), loadingCount$!]),
+        { defaultValue: undefined }
+      )
     ).resolves.toBe(undefined);
   });
 });

src/core/server/core_usage_data/core_usage_data_service.test.ts

@@ -8,9 +8,11 @@
 
 import type { ConfigPath } from '@kbn/config';
 import { BehaviorSubject, Observable } from 'rxjs';
-import { HotObservable } from 'rxjs/internal/testing/HotObservable';
 import { TestScheduler } from 'rxjs/testing';
 
+// eslint-disable-next-line @kbn/imports/no_unresolved_imports
+import { HotObservable } from 'rxjs/internal/testing/HotObservable';
+
 import { configServiceMock } from '../config/mocks';
 
 import { mockCoreContext } from '../core_context.mock';

src/core/server/core_usage_data/core_usage_data_service.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { Subject, Observable } from 'rxjs';
+import { Subject, Observable, firstValueFrom } from 'rxjs';
-import { takeUntil, first } from 'rxjs/operators';
+import { takeUntil } from 'rxjs/operators';
 import { get } from 'lodash';
 import { hasConfigPathIntersection, ChangedDeprecatedPaths } from '@kbn/config';
 
@@ -100,7 +100,7 @@ export class CoreUsageDataService
   constructor(core: CoreContext) {
     this.logger = core.logger.get('core-usage-stats-service');
     this.configService = core.configService;
-    this.stop$ = new Subject();
+    this.stop$ = new Subject<void>();
   }
 
   private async getSavedObjectUsageData(
@@ -383,7 +383,7 @@ export class CoreUsageDataService
   private async getNonDefaultKibanaConfigs(
     exposedConfigsToUsage: ExposedConfigsToUsage
   ): Promise<ConfigUsageData> {
-    const config = await this.configService.getConfig$().pipe(first()).toPromise();
+    const config = await firstValueFrom(this.configService.getConfig$());
     const nonDefaultConfigs = config.toRaw();
     const usedPaths = await this.configService.getUsedPaths();
     const exposedConfigsKeys = [...exposedConfigsToUsage.keys()];

src/core/server/deprecations/deprecations_service.ts

@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { take } from 'rxjs/operators';
+import { firstValueFrom } from 'rxjs';
 
 import { DeprecationsFactory } from './deprecations_factory';
 import { DomainDeprecationDetails, RegisterDeprecationsConfig } from './types';
@@ -144,10 +144,9 @@ export class DeprecationsService
   public async setup({ http }: DeprecationsSetupDeps): Promise<InternalDeprecationsServiceSetup> {
     this.logger.debug('Setting up Deprecations service');
 
-    const config = await this.configService
+    const config = await firstValueFrom(
-      .atPath<DeprecationConfigType>(deprecationConfig.path)
+      this.configService.atPath<DeprecationConfigType>(deprecationConfig.path)
-      .pipe(take(1))
+    );
-      .toPromise();
 
     this.deprecationsFactory = new DeprecationsFactory({
       logger: this.logger,

src/core/server/elasticsearch/elasticsearch_service.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { Observable, Subject } from 'rxjs';
+import { firstValueFrom, Observable, Subject } from 'rxjs';
-import { first, map, shareReplay, takeUntil } from 'rxjs/operators';
+import { map, shareReplay, takeUntil } from 'rxjs/operators';
 
 import { CoreService } from '../../types';
 import { CoreContext } from '../core_context';
@@ -41,7 +41,7 @@ export class ElasticsearchService
 {
   private readonly log: Logger;
   private readonly config$: Observable<ElasticsearchConfig>;
-  private stop$ = new Subject();
+  private stop$ = new Subject<void>();
   private kibanaVersion: string;
   private authHeaders?: IAuthHeadersStorage;
   private executionContextClient?: IExecutionContext;
@@ -60,7 +60,7 @@ export class ElasticsearchService
   public async preboot(): Promise<InternalElasticsearchServicePreboot> {
     this.log.debug('Prebooting elasticsearch service');
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     return {
       config: {
         hosts: config.hosts,
@@ -76,7 +76,7 @@ export class ElasticsearchService
   public async setup(deps: SetupDeps): Promise<InternalElasticsearchServiceSetup> {
     this.log.debug('Setting up elasticsearch service');
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
 
     this.authHeaders = deps.http.authRequestHeaders;
     this.executionContextClient = deps.executionContext;
@@ -112,7 +112,7 @@ export class ElasticsearchService
       throw new Error('ElasticsearchService needs to be setup before calling start');
     }
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
 
     // Log every error we may encounter in the connection to Elasticsearch
     this.esNodesCompatibility$.subscribe(({ isCompatible, message }) => {

src/core/server/environment/environment_service.ts

@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { take } from 'rxjs/operators';
+import { firstValueFrom } from 'rxjs';
 import { PathConfigType, config as pathConfigDef } from '@kbn/utils';
 import { CoreContext } from '../core_context';
 import { Logger } from '../logging';
@@ -49,9 +49,9 @@ export class EnvironmentService {
     // IMPORTANT: This code is based on the assumption that none of the configuration values used
     // here is supposed to change during preboot phase and it's safe to read them only once.
     const [pathConfig, serverConfig, pidConfig] = await Promise.all([
-      this.configService.atPath<PathConfigType>(pathConfigDef.path).pipe(take(1)).toPromise(),
+      firstValueFrom(this.configService.atPath<PathConfigType>(pathConfigDef.path)),
-      this.configService.atPath<HttpConfigType>(httpConfigDef.path).pipe(take(1)).toPromise(),
+      firstValueFrom(this.configService.atPath<HttpConfigType>(httpConfigDef.path)),
-      this.configService.atPath<PidConfigType>(pidConfigDef.path).pipe(take(1)).toPromise(),
+      firstValueFrom(this.configService.atPath<PidConfigType>(pidConfigDef.path)),
     ]);
 
     // Log unhandled rejections so that we can fix them in preparation for https://github.com/elastic/kibana/issues/77469

src/core/server/http/http_server.ts

@@ -19,7 +19,7 @@ import {
 import agent from 'elastic-apm-node';
 
 import type { Duration } from 'moment';
-import { Observable } from 'rxjs';
+import { firstValueFrom, Observable } from 'rxjs';
 import { take } from 'rxjs/operators';
 import apm from 'elastic-apm-node';
 import { Logger, LoggerFactory } from '../logging';
@@ -223,7 +223,7 @@ export class HttpServer {
     if (hasStarted) {
       this.log.debug('stopping http server');
 
-      const shutdownTimeout = await this.shutdownTimeout$.pipe(take(1)).toPromise();
+      const shutdownTimeout = await firstValueFrom(this.shutdownTimeout$.pipe(take(1)));
       await this.server.stop({ timeout: shutdownTimeout.asMilliseconds() });
 
       this.log.debug(`http server stopped`);

src/core/server/http/http_service.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { Observable, Subscription, combineLatest } from 'rxjs';
+import { Observable, Subscription, combineLatest, firstValueFrom } from 'rxjs';
-import { first, map } from 'rxjs/operators';
+import { map } from 'rxjs/operators';
 import { pick } from '@kbn/std';
 
 import type { RequestHandlerContext } from 'src/core/server';
@@ -84,7 +84,7 @@ export class HttpService
 
   public async preboot(deps: PrebootDeps): Promise<InternalHttpServicePreboot> {
     this.log.debug('setting up preboot server');
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
 
     const prebootSetup = await this.prebootServer.setup(config);
     prebootSetup.server.route({
@@ -147,7 +147,7 @@ export class HttpService
       }
     });
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
 
     const { registerRouter, ...serverContract } = await this.httpServer.setup(
       config,
@@ -196,7 +196,7 @@ export class HttpService
   }
 
   public async start() {
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     if (this.shouldListen(config)) {
       this.log.debug('stopping preboot server');
       await this.prebootServer.stop();

src/core/server/http/router/request.ts

@@ -9,7 +9,7 @@
 import { URL } from 'url';
 import uuid from 'uuid';
 import { Request, RouteOptionsApp, RequestApplicationState, RouteOptions } from '@hapi/hapi';
-import { Observable, fromEvent } from 'rxjs';
+import { Observable, fromEvent, NEVER } from 'rxjs';
 import { shareReplay, first, filter } from 'rxjs/operators';
 import { RecursiveReadonly } from '@kbn/utility-types';
 import { deepFreeze } from '@kbn/std';
@@ -216,6 +216,13 @@ export class KibanaRequest<
   }
 
   private getEvents(request: Request): KibanaRequestEvents {
+    if (!request.raw.res) {
+      return {
+        aborted$: NEVER,
+        completed$: NEVER,
+      };
+    }
+
     const completed$ = fromEvent<void>(request.raw.res, 'close').pipe(shareReplay(1), first());
     // the response's underlying connection was terminated prematurely
     const aborted$ = completed$.pipe(filter(() => !isCompleted(request)));

src/core/server/i18n/i18n_service.ts

@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { take } from 'rxjs/operators';
+import { firstValueFrom } from 'rxjs';
 import { Logger } from '../logging';
 import { IConfigService } from '../config';
 import { CoreContext } from '../core_context';
@@ -68,10 +68,9 @@ export class I18nService {
   }
 
   private async initTranslations(pluginPaths: string[]) {
-    const i18nConfig = await this.configService
+    const i18nConfig = await firstValueFrom(
-      .atPath<I18nConfigType>(i18nConfigDef.path)
+      this.configService.atPath<I18nConfigType>(i18nConfigDef.path)
-      .pipe(take(1))
+    );
-      .toPromise();
 
     const locale = i18nConfig.locale;
     this.log.debug(`Using locale: ${locale}`);

src/core/server/metrics/integration_tests/server_collector.test.ts

@@ -76,8 +76,8 @@ describe('ServerMetricsCollector', () => {
 
   it('collect disconnects requests infos', async () => {
     const never = new Promise((resolve) => undefined);
-    const disconnectRequested$ = new Subject(); // Controls the number of requests in the /disconnect endpoint
+    const disconnectRequested$ = new Subject<void>(); // Controls the number of requests in the /disconnect endpoint
-    const disconnectAborted$ = new Subject(); // Controls the abort event in the /disconnect endpoint
+    const disconnectAborted$ = new Subject<void>(); // Controls the abort event in the /disconnect endpoint
 
     router.get({ path: '/', validate: false }, async (ctx, req, res) => {
       return res.ok({ body: '' });

src/core/server/metrics/metrics_service.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { ReplaySubject } from 'rxjs';
+import { firstValueFrom, ReplaySubject } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { CoreService } from '../../types';
 import { CoreContext } from '../core_context';
 import { Logger } from '../logging';
@@ -38,10 +37,9 @@ export class MetricsService
   }
 
   public async setup({ http }: MetricsServiceSetupDeps): Promise<InternalMetricsServiceSetup> {
-    const config = await this.coreContext.configService
+    const config = await firstValueFrom(
-      .atPath<OpsConfigType>(opsConfig.path)
+      this.coreContext.configService.atPath<OpsConfigType>(opsConfig.path)
-      .pipe(first())
+    );
-      .toPromise();
 
     this.metricsCollector = new OpsMetricsCollector(http.server, {
       logger: this.logger,

src/core/server/plugins/discovery/plugins_discovery.test.ts

@@ -13,8 +13,8 @@ import mockFs from 'mock-fs';
 import { loggingSystemMock } from '../../logging/logging_system.mock';
 import { getEnvOptions, rawConfigServiceMock } from '../../config/mocks';
 
-import { from } from 'rxjs';
+import { firstValueFrom, from } from 'rxjs';
-import { first, map, toArray } from 'rxjs/operators';
+import { map, toArray } from 'rxjs/operators';
 import { resolve } from 'path';
 import { ConfigService, Env } from '../../config';
 import { PluginsConfig, PluginsConfigType, config } from '../plugins_config';
@@ -163,10 +163,7 @@ describe('plugins discovery system', () => {
       logger,
     };
 
-    pluginConfig = await configService
+    pluginConfig = await firstValueFrom(configService.atPath<PluginsConfigType>('plugins'));
-      .atPath<PluginsConfigType>('plugins')
-      .pipe(first())
-      .toPromise();
 
     // jest relies on the filesystem to get sourcemaps when using console.log
     // which breaks with the mocked FS, see https://github.com/tschaub/mock-fs/issues/234
@@ -195,7 +192,7 @@ describe('plugins discovery system', () => {
       { createCwd: false }
     );
 
-    const plugins = await plugin$.pipe(toArray()).toPromise();
+    const plugins = await firstValueFrom(plugin$.pipe(toArray()));
     const pluginNames = plugins.map((plugin) => plugin.name);
 
     expect(pluginNames).toHaveLength(4);
@@ -362,7 +359,7 @@ describe('plugins discovery system', () => {
       { createCwd: false }
     );
 
-    const plugins = await plugin$.pipe(toArray()).toPromise();
+    const plugins = await firstValueFrom(plugin$.pipe(toArray()));
     const pluginNames = plugins.map((plugin) => plugin.name);
 
     expect(pluginNames).toHaveLength(4);
@@ -401,7 +398,7 @@ describe('plugins discovery system', () => {
       { createCwd: false }
     );
 
-    const plugins = await plugin$.pipe(toArray()).toPromise();
+    const plugins = await firstValueFrom(plugin$.pipe(toArray()));
     const pluginNames = plugins.map((plugin) => plugin.name);
 
     expect(pluginNames).toEqual(['pluginA']);
@@ -423,7 +420,7 @@ describe('plugins discovery system', () => {
       { createCwd: false }
     );
 
-    const plugins = await plugin$.pipe(toArray()).toPromise();
+    const plugins = await firstValueFrom(plugin$.pipe(toArray()));
     const pluginNames = plugins.map((plugin) => plugin.name);
 
     expect(pluginNames).toHaveLength(5);
@@ -451,7 +448,7 @@ describe('plugins discovery system', () => {
       { createCwd: false }
     );
 
-    const plugins = await plugin$.pipe(toArray()).toPromise();
+    const plugins = await firstValueFrom(plugin$.pipe(toArray()));
     const pluginNames = plugins.map((plugin) => plugin.name);
 
     expect(pluginNames).toHaveLength(3);
@@ -536,7 +533,7 @@ describe('plugins discovery system', () => {
       let { plugin$ } = discover(new PluginsConfig(pluginConfig, env), coreContext, instanceInfo);
 
       expect(scanPluginSearchPathsMock).toHaveBeenCalledTimes(1);
-      let plugins = await plugin$.pipe(toArray()).toPromise();
+      let plugins = await firstValueFrom(plugin$.pipe(toArray()));
       let pluginNames = plugins.map((plugin) => plugin.name);
 
       expect(pluginNames).toHaveLength(3);
@@ -555,7 +552,7 @@ describe('plugins discovery system', () => {
       plugin$ = discover(new PluginsConfig(pluginConfig, env), coreContext, instanceInfo).plugin$;
 
       expect(scanPluginSearchPathsMock).toHaveBeenCalledTimes(2);
-      plugins = await plugin$.pipe(toArray()).toPromise();
+      plugins = await firstValueFrom(plugin$.pipe(toArray()));
       pluginNames = plugins.map((plugin) => plugin.name);
 
       expect(pluginNames).toHaveLength(3);

src/core/server/plugins/discovery/scan_plugin_search_paths.test.ts

@@ -12,6 +12,7 @@ import { toArray } from 'rxjs/operators';
 import { resolve } from 'path';
 import { scanPluginSearchPaths } from './scan_plugin_search_paths';
 import { PluginDiscoveryError } from './plugin_discovery_error';
+import { firstValueFrom } from 'rxjs';
 
 const KIBANA_ROOT = process.cwd();
 
@@ -82,7 +83,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths(scanPaths, logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(paths).toHaveLength(3);
     expect(errors).toHaveLength(0);
@@ -106,7 +107,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths([`${KIBANA_ROOT}/src/plugins`], logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(paths).toHaveLength(1);
     expect(errors).toHaveLength(0);
@@ -128,7 +129,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths([`${KIBANA_ROOT}/src/plugins`], logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(paths).toHaveLength(0);
     expect(errors).toHaveLength(1);
@@ -153,7 +154,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths([`${KIBANA_ROOT}/src/plugins`], logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(errors).toHaveLength(0);
     expect(paths).toHaveLength(4);
@@ -180,7 +181,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths([`${KIBANA_ROOT}/src/plugins`], logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(errors).toHaveLength(0);
     expect(paths).toHaveLength(1);
@@ -203,7 +204,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths([`${KIBANA_ROOT}/src/plugins`], logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(errors).toHaveLength(0);
     expect(paths).toHaveLength(5);
@@ -236,7 +237,7 @@ describe('scanPluginSearchPaths', () => {
     );
 
     const pluginOrErrors$ = scanPluginSearchPaths([`${KIBANA_ROOT}/plugins`], logger);
-    const { paths, errors } = extract(await pluginOrErrors$.pipe(toArray()).toPromise());
+    const { paths, errors } = extract(await firstValueFrom(pluginOrErrors$.pipe(toArray())));
 
     expect(errors).toHaveLength(0);
     expect(paths).toHaveLength(2);

src/core/server/plugins/discovery/scan_plugin_search_paths.ts

@@ -13,8 +13,8 @@ import { catchError, mergeMap } from 'rxjs/operators';
 import { Logger } from '../../logging';
 import { PluginDiscoveryError } from './plugin_discovery_error';
 
-const fsReadDir$ = bindNodeCallback<string, string[]>(readdir);
+const fsReadDir$ = bindNodeCallback<[string], [string[]]>(readdir);
-const fsStat$ = bindNodeCallback<PathLike, Stats>(stat);
+const fsStat$ = bindNodeCallback<[PathLike], [Stats]>(stat);
 
 const maxScanDepth = 5;
 

src/core/server/plugins/plugin.ts

@@ -8,8 +8,7 @@
 
 import { join } from 'path';
 import typeDetect from 'type-detect';
-import { Subject } from 'rxjs';
+import { firstValueFrom, Subject } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { isPromise } from '@kbn/std';
 import { isConfigSchema } from '@kbn/config-schema';
 
@@ -63,7 +62,7 @@ export class PluginWrapper<
     | AsyncPlugin<TSetup, TStart, TPluginsSetup, TPluginsStart>;
 
   private readonly startDependencies$ = new Subject<[CoreStart, TPluginsStart, TStart]>();
-  public readonly startDependencies = this.startDependencies$.pipe(first()).toPromise();
+  public readonly startDependencies = firstValueFrom(this.startDependencies$);
 
   constructor(
     public readonly params: {

src/core/server/plugins/plugins_service.ts

@@ -7,8 +7,8 @@
  */
 
 import Path from 'path';
-import { Observable } from 'rxjs';
+import { firstValueFrom, Observable } from 'rxjs';
-import { filter, first, map, tap, toArray } from 'rxjs/operators';
+import { filter, map, tap, toArray } from 'rxjs/operators';
 import { getFlattenedObject } from '@kbn/std';
 
 import { CoreService } from '../../types';
@@ -111,7 +111,7 @@ export class PluginsService implements CoreService<PluginsServiceSetup, PluginsS
   }
 
   public async discover({ environment }: PluginsServiceDiscoverDeps): Promise<DiscoveredPlugins> {
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
 
     const { error$, plugin$ } = discover(config, this.coreContext, {
       uuid: environment.instanceUuid,
@@ -151,7 +151,7 @@ export class PluginsService implements CoreService<PluginsServiceSetup, PluginsS
   public async preboot(deps: PluginsServicePrebootSetupDeps) {
     this.log.debug('Prebooting plugins service');
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     if (config.initialize) {
       await this.prebootPluginsSystem.setupPlugins(deps);
       this.registerPluginStaticDirs(deps, this.prebootUiPluginInternalInfo);
@@ -165,7 +165,7 @@ export class PluginsService implements CoreService<PluginsServiceSetup, PluginsS
   public async setup(deps: PluginsServiceSetupDeps) {
     this.log.debug('Setting up plugins service');
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
 
     let contracts = new Map<PluginName, unknown>();
     if (config.initialize) {
@@ -186,7 +186,7 @@ export class PluginsService implements CoreService<PluginsServiceSetup, PluginsS
   public async start(deps: PluginsServiceStartDeps) {
     this.log.debug('Plugins service starts plugins');
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     if (!config.initialize) {
       this.log.info(
         'Skipping `start` for `standard` plugins since plugin initialization is disabled.'
@@ -246,13 +246,13 @@ export class PluginsService implements CoreService<PluginsServiceSetup, PluginsS
       PluginDiscoveryErrorType.InvalidManifest,
     ];
 
-    const errors = await error$
+    const errors = await firstValueFrom(
-      .pipe(
+      error$.pipe(
         filter((error) => errorTypesToReport.includes(error.type)),
         tap((pluginError) => this.log.error(pluginError)),
         toArray()
       )
-      .toPromise();
+    );
     if (errors.length > 0) {
       throw new Error(
         `Failed to initialize plugins:${errors.map((err) => `\n\t${err.message}`).join('')}`
@@ -265,7 +265,7 @@ export class PluginsService implements CoreService<PluginsServiceSetup, PluginsS
       PluginName,
       { plugin: PluginWrapper; isEnabled: boolean }
     >();
-    const plugins = await plugin$.pipe(toArray()).toPromise();
+    const plugins = await firstValueFrom(plugin$.pipe(toArray()));
 
     // Register config descriptors and deprecations
     for (const plugin of plugins) {

src/core/server/saved_objects/migrations/kibana_migrator.test.ts

@@ -16,6 +16,7 @@ import { SavedObjectTypeRegistry } from '../saved_objects_type_registry';
 import { SavedObjectsType } from '../types';
 import { DocumentMigrator } from './core/document_migrator';
 import { ByteSizeValue } from '@kbn/config-schema';
+import { lastValueFrom } from 'rxjs';
 
 jest.mock('./core/document_migrator', () => {
   return {
@@ -134,7 +135,7 @@ describe('KibanaMigrator', () => {
     it('emits results on getMigratorResult$()', async () => {
       const options = mockV2MigrationOptions();
       const migrator = new KibanaMigrator(options);
-      const migratorStatus = migrator.getStatus$().pipe(take(3)).toPromise();
+      const migratorStatus = lastValueFrom(migrator.getStatus$().pipe(take(3)));
       migrator.prepareMigrations();
       await migrator.runMigrations();
 

src/core/server/saved_objects/saved_objects_service.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { Subject, Observable } from 'rxjs';
+import { Subject, Observable, firstValueFrom } from 'rxjs';
-import { first, filter, take, switchMap } from 'rxjs/operators';
+import { filter, take, switchMap } from 'rxjs/operators';
 import { CoreService } from '../../types';
 import {
   SavedObjectsClient,
@@ -314,14 +314,12 @@ export class SavedObjectsService
     this.setupDeps = setupDeps;
     const { http, elasticsearch, coreUsageData, deprecations } = setupDeps;
 
-    const savedObjectsConfig = await this.coreContext.configService
+    const savedObjectsConfig = await firstValueFrom(
-      .atPath<SavedObjectsConfigType>('savedObjects')
+      this.coreContext.configService.atPath<SavedObjectsConfigType>('savedObjects')
-      .pipe(first())
+    );
-      .toPromise();
+    const savedObjectsMigrationConfig = await firstValueFrom(
-    const savedObjectsMigrationConfig = await this.coreContext.configService
+      this.coreContext.configService.atPath<SavedObjectsMigrationConfigType>('migrations')
-      .atPath<SavedObjectsMigrationConfigType>('migrations')
+    );
-      .pipe(first())
-      .toPromise();
     this.config = new SavedObjectConfig(savedObjectsConfig, savedObjectsMigrationConfig);
 
     deprecations.getRegistry('savedObjects').registerDeprecations(
@@ -340,7 +338,7 @@ export class SavedObjectsService
       coreUsageData,
       logger: this.logger,
       config: this.config,
-      migratorPromise: this.migrator$.pipe(first()).toPromise(),
+      migratorPromise: firstValueFrom(this.migrator$),
       kibanaIndex,
       kibanaVersion: this.kibanaVersion,
     });

src/core/server/status/routes/integration_tests/status.test.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { BehaviorSubject } from 'rxjs';
+import { BehaviorSubject, firstValueFrom } from 'rxjs';
-import { first } from 'rxjs/operators';
 import supertest from 'supertest';
 import { omit } from 'lodash';
 
@@ -144,7 +143,7 @@ describe('GET /api/status', () => {
       build_number: 1234,
       build_snapshot: true,
     });
-    const metricsMockValue = await metrics.getOpsMetrics$().pipe(first()).toPromise();
+    const metricsMockValue = await firstValueFrom(metrics.getOpsMetrics$());
     expect(result.body.metrics).toEqual({
       last_updated: expect.any(String),
       collection_interval_in_millis: metrics.collectionInterval,

src/core/server/status/routes/status.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { Observable, combineLatest, ReplaySubject } from 'rxjs';
+import { Observable, combineLatest, ReplaySubject, firstValueFrom } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { schema } from '@kbn/config-schema';
 
 import { IRouter } from '../../http';
@@ -92,7 +91,7 @@ export const registerStatusRoute = ({
     async (context, req, res) => {
       const { version, buildSha, buildNum } = config.packageInfo;
       const versionWithoutSnapshot = version.replace(SNAPSHOT_POSTFIX, '');
-      const [overall, coreOverall, core, plugins] = await combinedStatus$.pipe(first()).toPromise();
+      const [overall, coreOverall, core, plugins] = await firstValueFrom(combinedStatus$);
 
       const { v8format = true, v7format = false } = req.query ?? {};
 
@@ -113,7 +112,7 @@ export const registerStatusRoute = ({
         });
       }
 
-      const lastMetrics = await metrics.getOpsMetrics$().pipe(first()).toPromise();
+      const lastMetrics = await firstValueFrom(metrics.getOpsMetrics$());
 
       const body: StatusHttpBody = {
         name: config.serverName,

src/core/server/status/status_service.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { Observable, combineLatest, Subscription, Subject } from 'rxjs';
+import { Observable, combineLatest, Subscription, Subject, firstValueFrom } from 'rxjs';
-import { map, distinctUntilChanged, shareReplay, take, debounceTime } from 'rxjs/operators';
+import { map, distinctUntilChanged, shareReplay, debounceTime } from 'rxjs/operators';
 import { isDeepStrictEqual } from 'util';
 
 import { CoreService } from '../../types';
@@ -65,7 +65,7 @@ export class StatusService implements CoreService<InternalStatusServiceSetup> {
     environment,
     coreUsageData,
   }: SetupDeps) {
-    const statusConfig = await this.config$.pipe(take(1)).toPromise();
+    const statusConfig = await firstValueFrom(this.config$);
     const core$ = this.setupCoreStatus({ elasticsearch, savedObjects });
     this.pluginsStatus = new PluginsStatusService({ core$, pluginDependencies });
 

src/core/server/ui_settings/ui_settings_service.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { Observable } from 'rxjs';
+import { firstValueFrom, Observable } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { mapToObject } from '@kbn/std';
 
 import { CoreService } from '../../types';
@@ -53,7 +52,7 @@ export class UiSettingsService
   public async preboot(): Promise<InternalUiSettingsServicePreboot> {
     this.log.debug('Prebooting ui settings service');
 
-    const { overrides } = await this.config$.pipe(first()).toPromise();
+    const { overrides } = await firstValueFrom(this.config$);
     this.overrides = overrides;
 
     this.register(getCoreSettings({ isDist: this.isDist }));
@@ -74,7 +73,7 @@ export class UiSettingsService
     savedObjects.registerType(uiSettingsType);
     registerRoutes(http.createRouter(''));
 
-    const config = await this.config$.pipe(first()).toPromise();
+    const config = await firstValueFrom(this.config$);
     this.overrides = config.overrides;
 
     return {

src/dev/build/lib/scan.ts

@@ -15,8 +15,8 @@ import { map, mergeAll, mergeMap } from 'rxjs/operators';
 // @ts-ignore
 import { assertAbsolute } from './fs';
 
-const getStat$ = Rx.bindNodeCallback(Fs.stat) as (path: string) => Rx.Observable<Fs.Stats>;
+const getStat$ = Rx.bindNodeCallback<[string], [Fs.Stats]>(Fs.stat);
-const getReadDir$ = Rx.bindNodeCallback(Fs.readdir) as (path: string) => Rx.Observable<string[]>;
+const getReadDir$ = Rx.bindNodeCallback<[string], [string[]]>(Fs.readdir);
 
 /**
  * Return an observable of all files in a directory, starting with the

src/dev/build/lib/scan_delete.ts

@@ -16,8 +16,8 @@ import { count, map, mergeAll, mergeMap } from 'rxjs/operators';
 // @ts-ignore
 import { assertAbsolute } from './fs';
 
-const getStat$ = Rx.bindNodeCallback<Fs.PathLike, Fs.Stats>(Fs.stat);
+const getStat$ = Rx.bindNodeCallback<[Fs.PathLike], [Fs.Stats]>(Fs.stat);
-const getReadDir$ = Rx.bindNodeCallback<string, string[]>(Fs.readdir);
+const getReadDir$ = Rx.bindNodeCallback<[string], [string[]]>(Fs.readdir);
 
 interface Options {
   directory: string;

src/dev/build/tasks/build_kibana_platform_plugins.ts

@@ -9,7 +9,7 @@
 import Path from 'path';
 
 import { REPO_ROOT } from '@kbn/utils';
-import { lastValueFrom } from '@kbn/std';
+import { lastValueFrom } from 'rxjs';
 import { CiStatsMetric } from '@kbn/dev-utils';
 import {
   runOptimizer,

src/dev/eslint/run_eslint_with_types.ts

@@ -16,7 +16,6 @@ import { mergeMap, reduce } from 'rxjs/operators';
 import { supportsColor } from 'chalk';
 import { run, createFailError } from '@kbn/dev-utils';
 import { REPO_ROOT } from '@kbn/utils';
-import { lastValueFrom } from '@kbn/std';
 
 import { PROJECTS } from '../typescript/projects';
 import { Project } from '../typescript/project';
@@ -61,7 +60,7 @@ export function runEslintWithTypes() {
       const concurrency = Math.max(1, Math.round((Os.cpus() || []).length / 2) || 1) || 1;
       log.info(`Linting ${projects.length} projects, ${concurrency} at a time`);
 
-      const failures = await lastValueFrom(
+      const failures = await Rx.lastValueFrom(
         Rx.from(projects).pipe(
           mergeMap(async (project) => {
             const configFilePath = Path.resolve(project.directory, 'types.eslint.config.js');

src/dev/typescript/concurrent_map.ts

@@ -8,7 +8,6 @@
 
 import * as Rx from 'rxjs';
 import { mergeMap, toArray, map } from 'rxjs/operators';
-import { lastValueFrom } from '@kbn/std';
 
 export async function concurrentMap<T, T2>(
   concurrency: number,
@@ -19,7 +18,7 @@ export async function concurrentMap<T, T2>(
     return [];
   }
 
-  return await lastValueFrom(
+  return await Rx.lastValueFrom(
     Rx.from(arr).pipe(
       // execute items in parallel based on concurrency
       mergeMap(async (item, index) => ({ index, result: await fn(item, index) }), concurrency),

src/dev/typescript/run_type_check_cli.ts

@@ -13,7 +13,6 @@ import * as Rx from 'rxjs';
 import { mergeMap, reduce } from 'rxjs/operators';
 import execa from 'execa';
 import { run, createFailError } from '@kbn/dev-utils';
-import { lastValueFrom } from '@kbn/std';
 
 import { PROJECTS } from './projects';
 import { buildTsRefs } from './build_ts_refs';
@@ -65,7 +64,7 @@ export async function runTypeCheckCli() {
           : ['--skipLibCheck', 'false']),
       ];
 
-      const failureCount = await lastValueFrom(
+      const failureCount = await Rx.lastValueFrom(
         Rx.from(projects).pipe(
           mergeMap(async (p) => {
             const relativePath = Path.relative(process.cwd(), p.tsConfigPath);

src/plugins/charts/public/services/active_cursor/active_cursor.test.ts

@@ -22,8 +22,8 @@ describe('ActiveCursor', () => {
 
     expect(activeCursor.activeCursor$).toMatchInlineSnapshot(`
       Subject {
-        "_isScalar": false,
         "closed": false,
+        "currentObservers": null,
         "hasError": false,
         "isStopped": false,
         "observers": Array [],

src/plugins/console/server/services/es_legacy_config_service.ts

@@ -6,8 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { Observable, Subscription } from 'rxjs';
+import { firstValueFrom, Observable, Subscription } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { ElasticsearchConfig } from 'kibana/server';
 
 export class EsLegacyConfigService {
@@ -45,7 +44,7 @@ export class EsLegacyConfigService {
     }
 
     if (!this.config) {
-      return this.config$.pipe(first()).toPromise();
+      return firstValueFrom(this.config$);
     }
 
     return this.config;

src/plugins/controls/public/control_group/embeddable/control_group_chaining_system.ts

@@ -59,7 +59,7 @@ export const ControlGroupChainingSystems: {
     onChildChange: ({ childOutputChangedId, childOrder, recalculateFilters$, getChild }) => {
       if (childOutputChangedId === childOrder.lastChildId) {
         // the last control's output has updated, recalculate filters
-        recalculateFilters$.next();
+        recalculateFilters$.next(null);
         return;
       }
 
@@ -75,6 +75,6 @@ export const ControlGroupChainingSystems: {
   NONE: {
     getContainerSettings: () => undefined,
     getPrecedingFilters: () => undefined,
-    onChildChange: ({ recalculateFilters$ }) => recalculateFilters$.next(),
+    onChildChange: ({ recalculateFilters$ }) => recalculateFilters$.next(null),
   },
 };

src/plugins/controls/public/control_types/time_slider/time_slider_embeddable.tsx

@@ -151,7 +151,7 @@ export class TimeSliderControlEmbeddable extends Embeddable<
     const min = value ? value[0] : null;
     const max = value ? value[1] : null;
     const hasRange =
-      this.componentState.range!.max !== undefined && this.componentState.range!.min !== undefined;
+      this.componentState.range?.max !== undefined && this.componentState.range?.min !== undefined;
 
     this.getCurrentDataView$().subscribe((dataView) => {
       const range: RangeFilterParams = {};

src/plugins/dashboard/public/application/hooks/use_dashboard_app_state.ts

@@ -310,7 +310,7 @@ export const useDashboardAppState = ({
        * the last saved state on save.
        */
       setLastSavedState(savedDashboardState);
-      dashboardBuildContext.$checkForUnsavedChanges.next();
+      dashboardBuildContext.$checkForUnsavedChanges.next(undefined);
       const updateLastSavedState = () => {
         setLastSavedState(
           savedObjectToDashboardState({

src/plugins/dashboard/public/application/lib/sync_dashboard_container_input.ts

@@ -60,7 +60,7 @@ export const syncDashboardContainerInput = (
       .getInput$()
       .subscribe(() => applyContainerChangesToState(syncDashboardContainerProps))
   );
-  subscriptions.add($onDashboardStateChange.subscribe(() => $triggerDashboardRefresh.next()));
+  subscriptions.add($onDashboardStateChange.subscribe(() => $triggerDashboardRefresh.next({})));
   subscriptions.add(
     getSessionURLObservable(history).subscribe(() => {
       $triggerDashboardRefresh.next({ force: true });

src/plugins/dashboard/public/application/lib/sync_dashboard_filter_state.ts

@@ -103,13 +103,14 @@ export const syncDashboardFilterState = ({
     .subscribe(() => applyFilters(queryString.getQuery(), filterManager.getFilters()));
 
   const timeRefreshSubscription = merge(
-    ...[timefilterService.getRefreshIntervalUpdate$(), timefilterService.getTimeUpdate$()]
+    timefilterService.getRefreshIntervalUpdate$(),
+    timefilterService.getTimeUpdate$()
   ).subscribe(() => {
-    $triggerDashboardRefresh.next();
+    $triggerDashboardRefresh.next({});
 
     // manually check for unsaved changes here because the time range is not stored on the dashboardState,
     // but it could trigger the unsaved changes badge.
-    $checkForUnsavedChanges.next();
+    $checkForUnsavedChanges.next(undefined);
   });
 
   const forceRefreshSubscription = timefilterService

src/plugins/dashboard/public/application/listing/__snapshots__/dashboard_listing.test.tsx.snap

@@ -25,9 +25,9 @@ exports[`after fetch When given a title that matches multiple dashboards, filter
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -39,10 +39,9 @@ exports[`after fetch When given a title that matches multiple dashboards, filter
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -129,7 +128,6 @@ exports[`after fetch When given a title that matches multiple dashboards, filter
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }
@@ -175,9 +173,9 @@ exports[`after fetch initialFilter 1`] = `
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -189,10 +187,9 @@ exports[`after fetch initialFilter 1`] = `
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -279,7 +276,6 @@ exports[`after fetch initialFilter 1`] = `
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }
@@ -324,9 +320,9 @@ exports[`after fetch renders all table rows 1`] = `
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -338,10 +334,9 @@ exports[`after fetch renders all table rows 1`] = `
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -428,7 +423,6 @@ exports[`after fetch renders all table rows 1`] = `
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }
@@ -473,9 +467,9 @@ exports[`after fetch renders call to action when no dashboards exist 1`] = `
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -487,10 +481,9 @@ exports[`after fetch renders call to action when no dashboards exist 1`] = `
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -577,7 +570,6 @@ exports[`after fetch renders call to action when no dashboards exist 1`] = `
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }
@@ -622,9 +614,9 @@ exports[`after fetch renders call to action with continue when no dashboards exi
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -636,10 +628,9 @@ exports[`after fetch renders call to action with continue when no dashboards exi
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -737,7 +728,6 @@ exports[`after fetch renders call to action with continue when no dashboards exi
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }
@@ -782,9 +772,9 @@ exports[`after fetch renders warning when listingLimit is exceeded 1`] = `
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -796,10 +786,9 @@ exports[`after fetch renders warning when listingLimit is exceeded 1`] = `
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -886,7 +875,6 @@ exports[`after fetch renders warning when listingLimit is exceeded 1`] = `
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }
@@ -931,9 +919,9 @@ exports[`after fetch showWriteControls 1`] = `
     application={
       Object {
         "applications$": BehaviorSubject {
-          "_isScalar": false,
           "_value": Map {},
           "closed": false,
+          "currentObservers": null,
           "hasError": false,
           "isStopped": false,
           "observers": Array [],
@@ -945,10 +933,9 @@ exports[`after fetch showWriteControls 1`] = `
           "navLinks": Object {},
         },
         "currentAppId$": Observable {
-          "_isScalar": false,
           "source": Subject {
-            "_isScalar": false,
             "closed": false,
+            "currentObservers": null,
             "hasError": false,
             "isStopped": false,
             "observers": Array [],
@@ -1005,7 +992,6 @@ exports[`after fetch showWriteControls 1`] = `
     theme={
       Object {
         "theme$": Observable {
-          "_isScalar": false,
           "_subscribe": [Function],
         },
       }

src/plugins/data/common/search/aggs/buckets/_terms_other_bucket_helper.ts

@@ -15,6 +15,7 @@ import {
   buildQueryFromFilters,
   Filter,
 } from '@kbn/es-query';
+import { lastValueFrom } from 'rxjs';
 import { AggGroupNames } from '../agg_groups';
 import { IAggConfigs } from '../agg_configs';
 import { IAggType } from '../agg_type';
@@ -342,8 +343,8 @@ export const createOtherBucketPostFlightRequest = (
 
       nestedSearchSource.setField('aggs', filterAgg);
 
-      const { rawResponse: response } = await nestedSearchSource
+      const { rawResponse: response } = await lastValueFrom(
-        .fetch$({
+        nestedSearchSource.fetch$({
           abortSignal,
           sessionId: searchSessionId,
           inspector: {
@@ -358,7 +359,7 @@ export const createOtherBucketPostFlightRequest = (
             }),
           },
         })
-        .toPromise();
+      );
 
       resp = mergeOtherBucketAggResponse(
         aggConfigs,

src/plugins/data/common/search/expressions/eql.ts

@@ -11,6 +11,7 @@ import { buildEsQuery } from '@kbn/es-query';
 import { ExpressionFunctionDefinition } from 'src/plugins/expressions/common';
 
 import { EqlSearchRequest } from '@elastic/elasticsearch/lib/api/typesWithBodyKey';
+import { lastValueFrom } from 'rxjs';
 import { RequestStatistics, RequestAdapter } from '../../../../inspector/common';
 import {
   ISearchGeneric,
@@ -143,7 +144,8 @@ export const getEqlFn = ({
       });
 
       try {
-        const response = await search<EqlSearchStrategyRequest, EqlSearchStrategyResponse>(
+        const response = await lastValueFrom(
+          search<EqlSearchStrategyRequest, EqlSearchStrategyResponse>(
             {
               params: {
                 index: args.index,
@@ -151,7 +153,8 @@ export const getEqlFn = ({
               },
             },
             { abortSignal, strategy: EQL_SEARCH_STRATEGY }
-        ).toPromise();
+          )
+        );
 
         const stats: RequestStatistics = {};
 

src/plugins/data/common/search/expressions/esdsl.ts

@@ -10,6 +10,7 @@ import { i18n } from '@kbn/i18n';
 import { buildEsQuery } from '@kbn/es-query';
 import { ExpressionFunctionDefinition } from 'src/plugins/expressions/common';
 
+import { lastValueFrom } from 'rxjs';
 import { EsRawResponse } from './es_raw_response';
 import { RequestStatistics, RequestAdapter } from '../../../../inspector/common';
 import { ISearchGeneric, KibanaContext } from '..';
@@ -125,7 +126,8 @@ export const getEsdslFn = ({
       });
 
       try {
-        const { rawResponse } = await search(
+        const { rawResponse } = await lastValueFrom(
+          search(
             {
               params: {
                 index: args.index,
@@ -134,7 +136,8 @@ export const getEsdslFn = ({
               },
             },
             { abortSignal }
-        ).toPromise();
+          )
+        );
 
         const stats: RequestStatistics = {};
 

src/plugins/data/common/search/search_source/search_source.test.ts

@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { of, throwError } from 'rxjs';
+import { lastValueFrom, of, throwError } from 'rxjs';
 import { IndexPattern } from '../..';
 import { SearchSource, SearchSourceDependencies, SortDirection } from './';
 import { AggConfigs, AggTypesRegistryStart } from '../../';
@@ -1240,7 +1240,7 @@ describe('SearchSource', () => {
         const fetch$ = searchSource.fetch$({});
         fetch$.subscribe(fetchSub);
 
-        const resp = await fetch$.toPromise();
+        const resp = await lastValueFrom(fetch$);
 
         expect(fetchSub.next).toHaveBeenCalledTimes(3);
         expect(fetchSub.complete).toHaveBeenCalledTimes(1);

src/plugins/data/common/search/search_source/search_source.ts

@@ -70,7 +70,7 @@ import {
   switchMap,
   tap,
 } from 'rxjs/operators';
-import { defer, EMPTY, from, Observable } from 'rxjs';
+import { defer, EMPTY, from, lastValueFrom, Observable } from 'rxjs';
 import type * as estypes from '@elastic/elasticsearch/lib/api/typesWithBodyKey';
 import { buildEsQuery, Filter } from '@kbn/es-query';
 import { normalizeSortRequest } from './normalize_sort_request';
@@ -325,9 +325,7 @@ export class SearchSource {
    * @removeBy 8.1
    */
   fetch(options: ISearchOptions = {}) {
-    return this.fetch$(options)
+    return lastValueFrom(this.fetch$(options)).then((r) => {
-      .toPromise()
-      .then((r) => {
       return r.rawResponse as estypes.SearchResponse<any>;
     });
   }

src/plugins/data/public/query/timefilter/timefilter.ts

@@ -32,10 +32,10 @@ export class Timefilter {
   // Fired when isTimeRangeSelectorEnabled \ isAutoRefreshSelectorEnabled are toggled
   private enabledUpdated$ = new BehaviorSubject(false);
   // Fired when a user changes the timerange
-  private timeUpdate$ = new Subject();
+  private timeUpdate$ = new Subject<void>();
   // Fired when a user changes the the autorefresh settings
-  private refreshIntervalUpdate$ = new Subject();
+  private refreshIntervalUpdate$ = new Subject<void>();
-  private fetch$ = new Subject();
+  private fetch$ = new Subject<void>();
 
   private _time: TimeRange;
   // Denotes whether setTime has been called, can be used to determine if the constructor defaults are being used.

src/plugins/data/public/query/timefilter/timefilter_service.mock.ts

@@ -23,7 +23,7 @@ const createSetupContractMock = () => {
     getTimeUpdate$: jest.fn(),
     getRefreshIntervalUpdate$: jest.fn(),
     getAutoRefreshFetch$: jest.fn(() => new Observable<() => void>()),
-    getFetch$: jest.fn(() => new Observable<() => void>()),
+    getFetch$: jest.fn().mockImplementation(() => new Observable<() => void>()),
     getTime: jest.fn(),
     setTime: jest.fn(),
     setRefreshInterval: jest.fn(),

src/plugins/data/public/search/session/session_helpers.test.ts

@@ -9,6 +9,7 @@
 import { waitUntilNextSessionCompletes$ } from './session_helpers';
 import { ISessionService, SessionService } from './session_service';
 import { BehaviorSubject } from 'rxjs';
+import { fakeSchedulers } from 'rxjs-marbles/jest';
 import { SearchSessionState } from './search_session_state';
 import { NowProviderInternalContract } from '../../now_provider';
 import { coreMock } from '../../../../../core/public/mocks';
@@ -62,7 +63,9 @@ describe('waitUntilNextSessionCompletes$', () => {
   afterEach(() => {
     jest.useRealTimers();
   });
-  test('emits when next session starts', () => {
+  test(
+    'emits when next session starts',
+    fakeSchedulers((advance) => {
       sessionService.start();
       let untrackSearch = sessionService.trackSearch({ abort: () => {} });
       untrackSearch();
@@ -79,10 +82,11 @@ describe('waitUntilNextSessionCompletes$', () => {
       untrackSearch();
 
       expect(next).not.toBeCalled();
-    jest.advanceTimersByTime(500);
+      advance(500);
       expect(next).not.toBeCalled();
-    jest.advanceTimersByTime(1000);
+      advance(1000);
       expect(next).toBeCalledTimes(1);
       expect(complete).toBeCalled();
-  });
+    })
+  );
 });

src/plugins/data/server/autocomplete/value_suggestions_route.ts

@@ -8,8 +8,7 @@
 
 import { schema } from '@kbn/config-schema';
 import { IRouter } from 'kibana/server';
-import { Observable } from 'rxjs';
+import { firstValueFrom, Observable } from 'rxjs';
-import { first } from 'rxjs/operators';
 import { getRequestAbortedSignal } from '../lib';
 import { getKbnServerError, reportServerError } from '../../../kibana_utils/server';
 import type { ConfigSchema } from '../../config';
@@ -42,7 +41,7 @@ export function registerValueSuggestionsRoute(router: IRouter, config$: Observab
       },
     },
     async (context, request, response) => {
-      const config = await config$.pipe(first()).toPromise();
+      const config = await firstValueFrom(config$);
       const { field: fieldName, query, filters, fieldMeta, method } = request.body;
       const { index } = request.params;
       const abortSignal = getRequestAbortedSignal(request.events.aborted$);

src/plugins/data/server/search/routes/bsearch.ts

@@ -6,7 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { catchError, first } from 'rxjs/operators';
+import { firstValueFrom } from 'rxjs';
+import { catchError } from 'rxjs/operators';
 import { BfetchServerSetup } from 'src/plugins/bfetch/server';
 import type { ExecutionContextSetup } from 'src/core/server';
 import apm from 'elastic-apm-node';
@@ -37,10 +38,8 @@ export function registerBsearchRoute(
         return executionContextService.withContext(executionContext, () => {
           apm.addLabels(executionContextService.getAsLabels());
 
-          return search
+          return firstValueFrom(
-            .search(requestData, restOptions)
+            search.search(requestData, restOptions).pipe(
-            .pipe(
-              first(),
               catchError((err) => {
                 // Re-throw as object, to get attributes passed to the client
                 // eslint-disable-next-line no-throw-literal
@@ -51,7 +50,7 @@ export function registerBsearchRoute(
                 };
               })
             )
-            .toPromise();
+          );
         });
       },
     };

src/plugins/data/server/search/search_service.test.ts

@@ -16,7 +16,7 @@ import { createIndexPatternsStartMock } from '../data_views/mocks';
 
 import { SearchService, SearchServiceSetupDependencies } from './search_service';
 import { bfetchPluginMock } from '../../../bfetch/server/mocks';
-import { of } from 'rxjs';
+import { lastValueFrom, of } from 'rxjs';
 import type {
   IEsSearchRequest,
   IEsSearchResponse,
@@ -182,7 +182,7 @@ describe('Search service', () => {
           throw new NoSearchIdInSessionError();
         });
 
-        const res = await mockScopedClient.search(searchRequest, options).toPromise();
+        const res = await lastValueFrom(mockScopedClient.search(searchRequest, options));
 
         const [request, callOptions] = mockStrategy.search.mock.calls[0];
         expect(callOptions).toBe(options);

src/plugins/data/server/search/search_service.ts

@@ -6,7 +6,7 @@
  * Side Public License, v 1.
  */
 
-import { from, Observable, throwError } from 'rxjs';
+import { firstValueFrom, from, Observable, throwError } from 'rxjs';
 import { pick } from 'lodash';
 import moment from 'moment';
 import {
@@ -19,7 +19,7 @@ import {
   SharedGlobalConfig,
   StartServicesAccessor,
 } from 'src/core/server';
-import { first, map, switchMap, tap, withLatestFrom } from 'rxjs/operators';
+import { map, switchMap, tap, withLatestFrom } from 'rxjs/operators';
 import { BfetchServerSetup } from 'src/plugins/bfetch/server';
 import { ExpressionsServerSetup } from 'src/plugins/expressions/server';
 import type {
@@ -221,11 +221,7 @@ export class SearchService implements Plugin<ISearchSetup, ISearchStart> {
 
     const aggs = this.aggsService.setup({ registerFunction: expressions.registerFunction });
 
-    this.initializerContext.config
+    firstValueFrom(this.initializerContext.config.create<ConfigSchema>()).then((value) => {
-      .create<ConfigSchema>()
-      .pipe(first())
-      .toPromise()
-      .then((value) => {
       if (value.search.aggs.shardDelay.enabled) {
         aggs.types.registerBucket(SHARD_DELAY_AGG_NAME, getShardDelayBucketAgg);
         expressions.registerFunction(aggShardDelay);

src/plugins/data/server/search/strategies/es_search/es_search_strategy.ts

@@ -6,8 +6,8 @@
  * Side Public License, v 1.
  */
 
-import { from, Observable } from 'rxjs';
+import { firstValueFrom, from, Observable } from 'rxjs';
-import { first, tap } from 'rxjs/operators';
+import { tap } from 'rxjs/operators';
 import type { Logger, SharedGlobalConfig } from 'kibana/server';
 import type { ISearchStrategy } from '../../types';
 import type { SearchUsage } from '../../collectors';
@@ -37,7 +37,7 @@ export const esSearchStrategyProvider = (
 
     const search = async () => {
       try {
-        const config = await config$.pipe(first()).toPromise();
+        const config = await firstValueFrom(config$);
         // @ts-expect-error params fall back to any, but should be valid SearchRequest params
         const { terminateAfter, ...requestParams } = request.params ?? {};
         const params = {