fix: `getCellSelection` throwing error (BLO-1193) by matthewlipski · Pull Request #2911 · TypeCellOS/BlockNote

matthewlipski · 2026-07-22T16:03:42Z

Summary

TableHandlesExtension.getCellSelection throws an error when the selection is within a table block but not actually a cell selection. For example, the selection can be a gap cursor at the start of the table.

In the static formatting toolbar example, the text alignment buttons call getCellSelection on selection change. In this example, if a table is at the start of the document, you can move the selection to a gap cursor above the table using the up arrow key or clicking in certain places to the side of the table. The text alignment buttons call getCellSelection which errors.

Closes #2748

Rationale

This is an uncommon error, but one that should be fixed either way.

Changes

Added additional checks before & after resolving cell positions to ensure they actually point to cells.

Impact

N/A

Testing

Added unit tests.

Screenshots/Video

N/A

Checklist

Code follows the project's coding standards.
Unit tests covering the new feature have been added.
All existing tests pass.
The documentation has been updated to reflect the new feature

Additional Notes

It seems strange that a button in the formatting toolbar should even need the table handles extension, so we may want to fix this also.

Summary by CodeRabbit

Bug Fixes
- Improved table selection handling for cursor positions outside table cells, including gap cursors near tables and nested blocks.
- Prevented invalid cell selections when the cursor is not inside a table cell.
Tests
- Added coverage for valid table-cell selections and non-table cursor positions.

…lock but outside cell

vercel · 2026-07-22T16:03:49Z

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coderabbitai · 2026-07-22T16:04:43Z

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: fc2e88f9-fcd2-4aa9-b029-d6862fb53dd5

📥 Commits

Reviewing files that changed from the base of the PR and between dee7880 and dba1c65.

📒 Files selected for processing (3)

packages/core/src/blocks/Table/TableExtension.test.ts
packages/core/src/blocks/defaultBlockTypeGuards.ts
packages/core/src/extensions/TableHandles/TableHandles.ts

📝 Walkthrough

Walkthrough

Table handle selection now validates resolved positions against actual table cell nodes, preventing invalid gap-cursor positions from reaching document resolution. Tests cover positions beside leading tables, nested blocks, and valid selections inside table cells.

Changes

Table cell selection validation

Layer / File(s)	Summary
Validate table cell positions `packages/core/src/blocks/defaultBlockTypeGuards.ts`, `packages/core/src/extensions/TableHandles/TableHandles.ts`	Adds `isTableCellNode` and uses it with negative-position checks in `getCellSelection()` to reject positions outside table cells.
Cover table handle selection cases `packages/core/src/blocks/Table/TableExtension.test.ts`	Adds tests for gap cursors beside leading tables or nested blocks, plus valid cell-coordinate extraction inside a table cell.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Suggested reviewers: nperez0111

Poem

A rabbit hops where tables lie,
No crashing cursor leaps awry.
Cells reveal their row and place,
Gap cursors find a safer space.
“Thump!” says Bun, and tests pass bright.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and directly describes the getCellSelection crash fix.
Description check	✅ Passed	The description follows the template and covers summary, rationale, changes, testing, and checklist.
Linked Issues check	✅ Passed	The changes address `#2748` by preventing out-of-cell selections from resolving and add tests for gap cursors and non-cell selections.
Out of Scope Changes check	✅ Passed	All changes are directly related to the table selection crash fix and its tests.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

✨ Finishing Touches

📝 Generate docstrings

Create stacked PR
Commit on current branch

🧪 Generate unit tests (beta)

Create PR with unit tests
Commit unit tests in branch static-toolbar-crash

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pkg-pr-new · 2026-07-22T16:07:40Z

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commit: dba1c65

github-actions · 2026-07-22T16:09:19Z

PR Preview Action v1.8.1
🚀 View preview at https://TypeCellOS.github.io/BlockNote/pr-preview/pr-2911/
Built to branch `gh-pages` at 2026-07-22 16:10 UTC. Preview will be ready when the GitHub Pages deployment is complete.

Fixed error when getCellSelection called while cursor is in table b…

dba1c65

…lock but outside cell

matthewlipski requested a review from YousefED July 22, 2026 16:17

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fix: `getCellSelection` throwing error (BLO-1193)#2911

fix: `getCellSelection` throwing error (BLO-1193)#2911
matthewlipski wants to merge 1 commit into
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static-toolbar-crash

matthewlipski commented Jul 22, 2026 •

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matthewlipski commented Jul 22, 2026 •

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