[7.17] [Lens] Fixes error on table when there is no data (#161953)

x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.test.ts

@@ -11,7 +11,7 @@ import { DatatableArgs } from './datatable';
 
 import { transposeTable } from './transpose_helpers';
 
-describe('transpose_helpes', () => {
+describe('transpose_helpers', () => {
   function buildTable(): Datatable {
     // 3 buckets, 2 metrics
     // first bucket goes A/B/C
@@ -290,4 +290,26 @@ describe('transpose_helpes', () => {
       1 + 18 - 2
     );
   });
+
+  it('should not fail for no data', () => {
+    const table = buildTable();
+    const updatedTable = {
+      ...table,
+      rows: [],
+    };
+    const args = buildArgs();
+    const updatedArgs = {
+      ...args,
+      columns: [
+        {
+          type: 'lens_datatable_column',
+          columnId: 'bucket1',
+          isTransposed: true,
+          transposable: false,
+        },
+      ],
+    } as DatatableArgs;
+    transposeTable(updatedArgs, updatedTable, buildFormatters());
+    expect(args.columns.length).toEqual(5);
+  });
 });

x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.ts

@@ -121,7 +121,7 @@ function updateColumnArgs(
 ) {
   args.columns = [...bucketsColumnArgs];
   // add first column from each group, then add second column for each group, ...
-  transposedColumnGroups[0].forEach((_, index) => {
+  transposedColumnGroups[0]?.forEach((_, index) => {
     transposedColumnGroups.forEach((transposedColumnGroup) => {
       args.columns.push(transposedColumnGroup[index]);
     });