[lexical-table] Bug Fix: Infer column header state from position during DOM import by Sathvik-Chowdary-Veerapaneni · Pull Request #8259 · facebook/lexical

Sathvik-Chowdary-Veerapaneni · 2026-03-26T04:16:01Z

Description

When importing a <th> element without a scope attribute, the header state is now inferred from position instead of always defaulting to ROW:

First row <th> → ROW header state
First column <th> → COLUMN header state
First row + first column → BOTH

This fixes the issue where column headers were not correctly propagated when inserting new rows via $insertTableRowAtSelection, because <th> elements in header columns were incorrectly marked as ROW instead of COLUMN.

Closes #8090

Test plan

Before

<th> elements imported via DOM always defaulted to ROW header type regardless of position
Inserting new rows lost column header state

After

Added 4 new unit tests for positioned <th> elements:
- <th> in first row first column → BOTH
- <th> in first column of non-first row → COLUMN
- <th> in <thead> non-first column → ROW
- Detached <th> → ROW (unchanged fallback)
All existing unit tests pass
pnpm run ci-check passes

When a <th> element has no scope attribute, infer header state from its position in the table instead of always defaulting to ROW: - First row <th> → ROW header state - First column <th> → COLUMN header state - First row + first column → BOTH This ensures that column headers imported from HTML are correctly propagated when inserting new rows via $insertTableRowAtSelection. Closes facebook#8090

Add tests verifying that <th> elements get correct header state based on position: BOTH for first-row first-column, COLUMN for first-column in non-first row, and ROW for non-first-column in thead.

vercel · 2026-03-26T04:16:06Z

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Project	Deployment	Actions	Updated (UTC)
lexical	Ready	Preview, Comment	Mar 26, 2026 8:35pm
lexical-playground	Ready	Preview, Comment	Mar 26, 2026 8:35pm

etrepum · 2026-03-26T19:30:39Z

packages/lexical-table/src/LexicalTableCellNode.ts

+      // Infer header state from position when no scope is specified
+      const parentRow = domNode_.parentElement;
+      const isFirstRow =
+        parentRow instanceof HTMLTableRowElement &&


It's best to avoid using instanceof for DOM because it won't work across certain contexts which is why we have isHTMLElement and comparisons with tagName instead.

makes sense, switched to isHTMLElement() with tagName checks

etrepum · 2026-03-26T19:31:22Z

packages/lexical-table/src/LexicalTableCellNode.ts

+      const parentRow = domNode_.parentElement;
+      const isFirstRow =
+        parentRow instanceof HTMLTableRowElement &&
+        (parentRow.parentElement?.nodeName.toLowerCase() === 'thead' ||


For mostly historical reasons nullish coalescing isn't used in lexical outside of tests and the playground

got it, replaced with an explicit isHTMLElement() guard

etrepum · 2026-03-26T19:34:06Z

packages/lexical-table/src/LexicalTableCellNode.ts

-      headerState = TableCellHeaderStates.ROW;
+      // Infer header state from position when no scope is specified
+      const parentRow = domNode_.parentElement;
+      const isFirstRow =


This name is a bit misleading because if it's in a thead it may not be the first row

good point, renamed to isInHeaderRow

etrepum · 2026-03-26T19:42:57Z

packages/lexical-table/src/LexicalTableCellNode.ts

+      // Fallback for detached elements
+      if (headerState === TableCellHeaderStates.NO_STATUS) {
+        headerState = TableCellHeaderStates.ROW;
+      }


I don't think we need to worry about detached elements, the unit test can be updated to have semantically correct input with a table ancestor. The extension and legacy plugin for tables has transforms that would remove any TableCellNode or TableRowNode that doesn't have the correct TableNode -> TableRowNode -> TableCellNode hierarchy.

updated the test to use a proper table > tr > th structure

etrepum · 2026-03-26T19:43:43Z

The title of this PR doesn't match the template https://raw.githubusercontent.com/facebook/lexical/refs/heads/main/.github/pull_request_template.md

etrepum · 2026-03-26T20:08:21Z

pnpm run ci-check is failing and must pass for any PR before it can be accepted

… structure - Replace instanceof HTMLTableRowElement with isHTMLElement() and tagName checks - Remove nullish coalescing in favor of explicit isHTMLElement guards - Rename isFirstRow to isInHeaderRow for clarity - Remove unnecessary comments - Update test to use proper table > tr > th structure instead of detached element

Sathvik-Chowdary-Veerapaneni · 2026-03-27T14:10:13Z

updated the PR body to match the template (Description + Before/After test plan). ci-check passes locally — tsc, flow, prettier, lint all clean.

Sathvik-Chowdary-Veerapaneni added 2 commits March 26, 2026 00:14

test(table): add tests for column header inference during DOM import

b25e2a5

Add tests verifying that <th> elements get correct header state based on position: BOTH for first-row first-column, COLUMN for first-column in non-first row, and ROW for non-first-column in thead.

Sathvik-Chowdary-Veerapaneni requested review from acywatson, etrepum, fantactuka, ivailop7, potatowagon, takuyakanbr and zurfyx as code owners March 26, 2026 04:16

meta-cla bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Mar 26, 2026

vercel bot deployed to Preview – lexical March 26, 2026 04:16 View deployment

vercel bot deployed to Preview – lexical-playground March 26, 2026 04:17 View deployment

etrepum reviewed Mar 26, 2026

View reviewed changes

Sathvik-Chowdary-Veerapaneni changed the title ~~table: infer column header state from position during DOM import~~ [lexical-table] Bug Fix: Infer column header state from position during DOM import Mar 26, 2026

vercel bot deployed to Preview – lexical March 26, 2026 20:34 View deployment

vercel bot deployed to Preview – lexical-playground March 26, 2026 20:35 View deployment

etrepum added the extended-tests Run extended e2e tests on a PR label Mar 27, 2026

etrepum approved these changes Mar 28, 2026

View reviewed changes

etrepum added this pull request to the merge queue Mar 28, 2026

Merged via the queue into facebook:main with commit 7f061d3 Mar 28, 2026
64 checks passed

etrepum mentioned this pull request Apr 9, 2026

v0.43.0 #8319

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[lexical-table] Bug Fix: Infer column header state from position during DOM import#8259

[lexical-table] Bug Fix: Infer column header state from position during DOM import#8259
etrepum merged 3 commits intofacebook:mainfrom
Sathvik-Chowdary-Veerapaneni:table-column-header-import-8090

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