From 516c49402cf68fe2e0e13e07c72c8236a879ee5c Mon Sep 17 00:00:00 2001
From: Stratoula Kalafateli <efstratia.kalafateli@elastic.co>
Date: Mon, 17 Jul 2023 10:45:22 +0300
Subject: [PATCH] [Lens] Fixes error on table when there is no data (#161953)

## Summary

Closes https://github.com/elastic/kibana/issues/161948

Fixes the bug described in the issue. The bug is happening only for the
table viz.

<img width="1664" alt="image"
src="https://github.com/elastic/kibana/assets/17003240/9646edcc-005d-4d2c-919a-097a673d730e">

### Checklist

- [ ] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios

(cherry picked from commit 6550793b4fe793ad53072bddc51118e43414e7ad)
---
 .../datatable/transpose_helpers.test.ts       | 24 ++++++++++++++++++-
 .../datatable/transpose_helpers.ts            |  2 +-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.test.ts b/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.test.ts
index 2a7461187c7716..35a96a5fd15244 100644
--- a/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.test.ts
+++ b/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);
+  });
 });
diff --git a/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.ts b/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.ts
index 00e0de71395d36..ef07a87cfb9e10 100644
--- a/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.ts
+++ b/x-pack/plugins/lens/common/expressions/datatable/transpose_helpers.ts
@@ -118,7 +118,7 @@ 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]);
     });