Column '{colId}' variant function returned u...

Warnings reference › variant-fn-token:*:*

Identifier

variant-fn-token:*:*

Raised by

The grid (rendering)

Since

1.0.1

What happened

The variant function ran and returned a token that is neither built in nor registered. The set of tokens is finite and known, which is what lets the grid style them with classes, so an unknown one cannot be painted: the fallback is used. Returning null or undefined is the supported way to say "no variant" and is not reported.

The fix

Return one of the registered or built-in tokens, or register the one you are returning.

Reference

Covered in full at the API reference.