[lens] significant terms convert to lens (#159580)

Part of https://github.com/elastic/kibana/issues/154307

Update convert to lens functionality to support significant terms
aggregation

<img width="500" alt="Screen Shot 2023-06-13 at 8 58 09 AM"
src="949199ee-24e2-45d0-84b1-512698abecb4">

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>
Co-authored-by: Stratoula Kalafateli <efstratia.kalafateli@elastic.co>

src/plugins/visualizations/common/convert_to_lens/lib/buckets/index.ts

@@ -21,6 +21,7 @@ import { getFieldNameFromField, getLabel, isSchemaConfig } from '../utils';
 
 export type BucketAggs =
   | BUCKET_TYPES.TERMS
+  | BUCKET_TYPES.SIGNIFICANT_TERMS
   | BUCKET_TYPES.DATE_HISTOGRAM
   | BUCKET_TYPES.FILTERS
   | BUCKET_TYPES.RANGE
@@ -28,6 +29,7 @@ export type BucketAggs =
 
 const SUPPORTED_BUCKETS: string[] = [
   BUCKET_TYPES.TERMS,
+  BUCKET_TYPES.SIGNIFICANT_TERMS,
   BUCKET_TYPES.DATE_HISTOGRAM,
   BUCKET_TYPES.FILTERS,
   BUCKET_TYPES.RANGE,
@@ -64,6 +66,7 @@ export const getBucketColumns = (
     case BUCKET_TYPES.HISTOGRAM:
       return convertToRangeColumn(agg.aggId ?? '', agg.aggParams, label, dataView, isSplit);
     case BUCKET_TYPES.TERMS:
+    case BUCKET_TYPES.SIGNIFICANT_TERMS:
       const fieldName = getFieldNameFromField(agg.aggParams.field);
       if (!fieldName) {
         return null;

src/plugins/visualizations/common/convert_to_lens/lib/convert/terms.test.ts

@@ -244,6 +244,40 @@ describe('convertToDateHistogramColumn', () => {
         mockConvertMetricToColumns.mockReturnValue(metricColumns);
       },
     ],
+    [
+      'significant terms column',
+      [
+        aggId,
+        {
+          agg: {
+            aggType: BUCKET_TYPES.SIGNIFICANT_TERMS,
+            aggParams: {
+              field: stubLogstashDataView.fields[0].name,
+              size: 5,
+            },
+          } as SchemaConfig<BUCKET_TYPES.SIGNIFICANT_TERMS>,
+          dataView: stubLogstashDataView,
+          aggs,
+          metricColumns,
+          visType,
+        },
+        '',
+        false,
+      ],
+      {
+        operationType: 'terms',
+        sourceField: stubLogstashDataView.fields[0].name,
+        isBucketed: true,
+        params: {
+          size: 5,
+          include: [],
+          exclude: [],
+          orderBy: { type: 'significant' },
+          orderDirection: 'desc',
+        },
+      },
+      () => {},
+    ],
   ])('should return %s', (_, input, expected, actions) => {
     actions();
     if (expected === null) {

src/plugins/visualizations/common/convert_to_lens/lib/convert/terms.ts

@@ -89,20 +89,34 @@ export const convertToTermsParams = ({
   aggs,
   metricColumns,
   visType,
-}: CommonBucketConverterArgs<BUCKET_TYPES.TERMS>): TermsParams | null => {
+}: CommonBucketConverterArgs<
+  BUCKET_TYPES.TERMS | BUCKET_TYPES.SIGNIFICANT_TERMS
+>): TermsParams | null => {
   if (!agg.aggParams) {
     return null;
   }
 
+  const size = agg.aggParams.size ?? 10;
+  const exclude = agg.aggParams.exclude ? filterOutEmptyValues(agg.aggParams.exclude) : [];
+  const include = agg.aggParams.include ? filterOutEmptyValues(agg.aggParams.include) : [];
+
+  if (agg.aggType === BUCKET_TYPES.SIGNIFICANT_TERMS) {
+    return {
+      size: agg.aggParams.size ?? 10,
+      orderDirection: 'desc',
+      include,
+      exclude,
+      orderBy: { type: 'significant' },
+    };
+  }
+
   const orderByWithAgg = getOrderByWithAgg({ agg, dataView, aggs, metricColumns, visType });
   if (orderByWithAgg === null) {
     return null;
   }
 
-  const exclude = agg.aggParams.exclude ? filterOutEmptyValues(agg.aggParams.exclude) : [];
-  const include = agg.aggParams.include ? filterOutEmptyValues(agg.aggParams.include) : [];
   return {
-    size: agg.aggParams.size ?? 10,
+    size,
     include,
     exclude,
     includeIsRegex: Boolean(include.length && agg.aggParams.includeIsRegex),
@@ -117,7 +131,13 @@ export const convertToTermsParams = ({
 
 export const convertToTermsColumn = (
   aggId: string,
-  { agg, dataView, aggs, metricColumns, visType }: CommonBucketConverterArgs<BUCKET_TYPES.TERMS>,
+  {
+    agg,
+    dataView,
+    aggs,
+    metricColumns,
+    visType,
+  }: CommonBucketConverterArgs<BUCKET_TYPES.TERMS | BUCKET_TYPES.SIGNIFICANT_TERMS>,
   label: string,
   isSplit: boolean
 ): TermsColumn | null => {

src/plugins/visualizations/common/convert_to_lens/types/params.ts

@@ -30,6 +30,7 @@ export interface TermsParams extends FormatParams {
   orderBy:
     | { type: 'alphabetical'; fallback?: boolean }
     | { type: 'rare'; maxDocCount: number }
+    | { type: 'significant' }
     | { type: 'column'; columnId: string }
     | { type: 'custom' };
   orderAgg?: Column;