Home > @microsoft/api-extractor-model > ApiReadonlyMixin > isBaseClassOf

ApiReadonlyMixin.isBaseClassOf() function

A type guard that tests whether the specified ApiItem subclass extends the ApiReadonlyMixin mixin.

Signature:

function isBaseClassOf(apiItem: ApiItem): apiItem is ApiReadonlyMixin;

Parameters

Parameter	Type	Description
apiItem	ApiItem

Returns:

apiItem is ApiReadonlyMixin

Remarks

The JavaScript instanceof operator cannot be used to test for mixin inheritance, because each invocation of the mixin function produces a different subclass. (This could be mitigated by Symbol.hasInstance, however the TypeScript type system cannot invoke a runtime test.)