TanStack Table version

v8.21.3

Framework/Library version

React v18

Describe the bug and the steps to reproduce it

This is a very similar issue to #5444
Due to this type not being exported, creating declaration files for objects that uses columnHelper.group throws a TypeScript error:

Exported variable 'foo' has or is using name 'GroupColumnDefBase' from external module "/.../@tanstack/table-core/build/lib/types" but cannot be named.

Exporting this variable resolves this issue

Your Minimal, Reproducible Example - (Sandbox Highly Recommended)

Screenshots or Videos (Optional)

No response

Do you intend to try to help solve this bug with your own PR?

Yes

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