Bugfix/reporting png is cancelled (#37513) (#37685)

* Making sure we have bindings properly set with our Classes + tests

x-pack/plugins/reporting/common/cancellation_token.test.ts

@@ -0,0 +1,58 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { CancellationToken } from './cancellation_token';
+
+describe('Cancellation Token', () => {
+  it('registers callbacks for cancellation events', () => {
+    const cancellationToken = new CancellationToken();
+    const onCancelled = jest.fn();
+    cancellationToken.on(onCancelled);
+    cancellationToken.cancel();
+
+    expect(onCancelled).toBeCalled();
+  });
+
+  it('emits a cancellation event immediately when already cancelled', () => {
+    const cancellationToken = new CancellationToken();
+    const onCancelled = jest.fn();
+    cancellationToken.cancel();
+    cancellationToken.on(onCancelled);
+
+    expect(onCancelled).toBeCalled();
+  });
+
+  it('binds the `on` method properly so that it can be passed around', () => {
+    const cancellationToken = new CancellationToken();
+    const onCancelled = jest.fn();
+    const unboundOn = cancellationToken.on;
+
+    cancellationToken.cancel();
+    unboundOn(onCancelled);
+
+    expect(onCancelled).toBeCalled();
+  });
+
+  it('binds the `cancel` method properly so that it can be passed around', () => {
+    const cancellationToken = new CancellationToken();
+    const onCancelled = jest.fn();
+    const unboundCancel = cancellationToken.cancel;
+
+    unboundCancel();
+    cancellationToken.on(onCancelled);
+
+    expect(onCancelled).toBeCalled();
+  });
+
+  it('throws an error when the callback is not a function', () => {
+    const cancellationToken = new CancellationToken();
+
+    expect(() => {
+      // @ts-ignore
+      cancellationToken.on('cool!');
+    }).toThrowError('Expected callback to be a function');
+  });
+});

x-pack/plugins/reporting/common/cancellation_token.ts

@@ -8,14 +8,14 @@ import { isFunction } from 'lodash';
 
 export class CancellationToken {
   private isCancelled: boolean;
-  private _callbacks: any[];
+  private _callbacks: Function[];
 
   constructor() {
     this.isCancelled = false;
     this._callbacks = [];
   }
 
-  on(callback: Function) {
+  public on = (callback: Function) => {
     if (!isFunction(callback)) {
       throw new Error('Expected callback to be a function');
     }
@@ -26,10 +26,10 @@ export class CancellationToken {
     }
 
     this._callbacks.push(callback);
-  }
+  };
 
-  cancel() {
+  public cancel = () => {
     this.isCancelled = true;
     this._callbacks.forEach(callback => callback());
-  }
+  };
 }

x-pack/plugins/reporting/export_types/printable_pdf/server/execute_job/index.js

@@ -58,8 +58,7 @@ function executeJobFn(server) {
       }))
     );
 
-    const boundCancelOn = cancellationToken.on.bind(cancellationToken);
-    const stop$ = Rx.fromEventPattern(boundCancelOn);
+    const stop$ = Rx.fromEventPattern(cancellationToken.on);
 
     return process$.pipe(takeUntil(stop$)).toPromise();
   });

x-pack/plugins/reporting/server/lib/esqueue/__tests__/helpers/cancellation_token.js

@@ -17,14 +17,12 @@ describe('CancellationToken', function () {
   describe('on', function () {
     [true, null, undefined, 1, 'string', {}, []].forEach(function (value) {
       it(`should throw an Error if value is ${value}`, function () {
-        const boundOn = cancellationToken.on.bind(cancellationToken);
-        expect(boundOn).withArgs(value).to.throwError();
+        expect(cancellationToken.on).withArgs(value).to.throwError();
       });
     });
 
     it('accepts a function', function () {
-      const boundOn = cancellationToken.on.bind(cancellationToken);
-      expect(boundOn).withArgs(function () {}).not.to.throwError();
+      expect(cancellationToken.on).withArgs(function () {}).not.to.throwError();
     });
 
     it(`calls function if cancel has previously been called`, function () {
@@ -37,8 +35,7 @@ describe('CancellationToken', function () {
 
   describe('cancel', function () {
     it('should be a function accepting no parameters', function () {
-      const boundCancel = cancellationToken.cancel.bind(cancellationToken);
-      expect(boundCancel).withArgs().to.not.throwError();
+      expect(cancellationToken.cancel).withArgs().to.not.throwError();
     });
 
     it('should call a single callback', function () {