[nstepien]

Column.frozen now only accepts false, 'start', or 'end'. When 'start' and 'end' arrived in beta.60 (#4034), true stayed on as an alias for 'start' so that 6.x code kept working. 7.0.0 drops the alias. Without it, the type is just Maybe<ColumnFrozen>, and the grid no longer has to convert true to 'start'.

Breaking change

- { key: 'id', name: 'ID', frozen: true }
+ { key: 'id', name: 'ID', frozen: 'start' }

Column.frozen is false | 'start' | 'end'. true, which was accepted as an alias for 'start', is now a type error.

Changes

• Column.frozen is typed Maybe<ColumnFrozen>, and its JSDoc no longer mentions the alias. useCalculatedColumns now uses rawColumn.frozen ?? false instead of converting true.
• getColSpan and the column sort in useCalculatedColumns compare frozen with false first, then with 'start', since unfrozen columns are the most common, then start-frozen ones.
• SelectColumn and the group-by columns of TreeDataGrid use frozen: 'start'.
• README: the frozen entry drops the backward-compatibility wording, and the ColumnFrozen "See also" link points to the renamed anchor (#frozen-maybecolumnfrozen).
• Removed the test that checked frozen: true is treated as 'start'. The other tests now use 'start'.
• Boolean expressions such as frozen: i < 5 used to type-check because they evaluate to true | false. They are type errors now, so the website demos (ColumnSpanning, MillionCells, ScrollToCell, VariableRowHeight) and tests (colSpan, startFrozen, keyboardNavigation, scrollToCell) use i < 5 ? 'start' : false. Apps that compute frozen from a boolean need the same change.

Verification

vp run ci passes. I also built the package with vp pack and type-checked a scratch consumer against lib/index.d.ts with tsc --strict, both with and without --exactOptionalPropertyTypes: 'start', 'end', false, null, and undefined are accepted, and true is a type error.

🤖 Generated with Claude Code

[codecov-commenter]

⚠️ Please install the to ensure uploads and comments are reliably processed by Codecov.

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 99.27%. Comparing base (5e7977b) to head (f2f72b6).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4260   +/-   ##
=======================================
  Coverage   99.27%   99.27%           
=======================================
  Files          44       44           
  Lines        2204     2204           
  Branches      965      965           
=======================================
  Hits         2188     2188           
  Misses         16       16           

Files with missing lines	Coverage Δ
src/Columns.tsx	100.00% <ø> (ø)
src/TreeDataGrid.tsx	98.66% <ø> (ø)
src/hooks/useCalculatedColumns.ts	100.00% <100.00%> (ø)

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.