fix: coerce accessor key to string during column creation

[schardev]

This is based on the PR by @jpedroh (https://github.com/TanStack/table/pull/4835)

During render, if the accessorKey was not a string, e.g. a number, it would result in an error when trying to normalize it during column creation, because it was trying to access methods which are not available in a number (replace and include). This PR forces the accessor key to be constructed as a string during column creation, thus removing this bug.

fixes https://github.com/TanStack/table/issues/4815

Summary by CodeRabbit

Release Notes

New Features

• Columns now accept numeric array indices as accessor keys. Tables can be configured using integer indices (0, 1, 2, etc.) alongside traditional string-based keys, providing enhanced flexibility when working with array-based data structures.

[changeset-bot[bot]]

⚠️ No Changeset found

Latest commit: 329cbce1f4250a717a54144ed28630b252b7c771

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[coderabbitai[bot]]

Walkthrough

This PR enables support for numeric array indices as accessorKey values in column definitions. The changes update the type signature to accept number in addition to string, implement normalization logic to coerce numeric keys to strings internally, and add test coverage validating the functionality.

Changes

Cohort / File(s)	Change Summary
Type definition update packages/table-core/src/types.ts	Updates ColumnDefResolved.accessorKey property from string to string | number to allow numeric array indices
Accessor key normalization packages/table-core/src/core/column.ts	Implements conditional coercion of resolvedColumnDef.accessorKey to string when defined, enabling numeric keys to work with downstream accessor logic
Test coverage packages/react-table/tests/core/core.test.tsx	Adds import for '@testing-library/jest-dom/vitest' and new test case verifying numeric indices (0, 1, 2) as accessorKey values render headers and data correctly

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

• Focus areas for review:
  • Verify the string coercion logic in column.ts handles all edge cases (undefined, null, numeric values)
  • Confirm the test case properly validates the documented array-index accessor behavior
  • Ensure type broadening to string | number doesn't introduce unexpected behavior downstream

Poem

🐰 Numeric keys once caused a fright, But now they're coerced to strings just right! Arrays indexed, clean and true, Your table renders fresh and new! 🎉

Pre-merge checks and finishing touches

❌ Failed checks (2 warnings)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The PR description references the bug fix and linked issue but does not follow the required template structure with sections for 'Changes', 'Checklist', and 'Release Impact'.	Provide a description following the template with '🎯 Changes' section, '✅ Checklist' with contribution verification, and '🚀 Release Impact' with changeset information.
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (3 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: coercing accessor keys to strings during column creation, which directly addresses the bug fix.
Linked Issues check	✅ Passed	The PR successfully addresses issue #4815 by coercing numeric accessorKey values to strings, allowing array indices to work without crashing.
Out of Scope Changes check	✅ Passed	All changes (type updates, string coercion in column creation, and test coverage) are directly scoped to fixing the array-index accessorKey bug.

✨ Finishing touches

• [ ] 📝 Generate docstrings

🧪 Generate unit tests (beta)

• [ ] Create PR with unit tests
• [ ] Post copyable unit tests in a comment

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