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ApiOptionalMixin.isBaseClassOf() function

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

Signature:

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

Parameters

Parameter	Type	Description
apiItem	ApiItem

Returns:

apiItem is ApiOptionalMixin

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.)