Column '{colId}' variant.when[{i}] uses unknown operator '{op}'. Valid operators (spec 9.3): {list}.

Warnings reference › variant-op:*:*

Identifier

variant-op:*:*

Raised by

The grid (rendering)

Since

1.0.1

What happened

One clause of a when list names an operator the matcher does not implement. That clause is skipped - the others still apply, in order, first match winning - so cells that the clause would have coloured fall through to a later clause or to the fallback.

The fix

Use one of the operators listed in the message.

The smallest fix

variant: { when: [{ op: 'lt', value: 0, variant: 'danger' }] }

Reference

Covered in full at the API reference.