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Vitest · Function

expectTypeOf

expectTypeOf provides compile-time assertions for TypeScript types in Vitest. It can compare types directly or inspect properties, function arguments, return values, arrays, promises, and unions.

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Syntax

expectTypeOf<T>(a?: unknown): ExpectTypeOf
expectTypeOf(a?: unknown).toEqualTypeOf<T>()

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  • toEqualTypeOf
  • toExtend
  • toMatchObjectType
  • extract
  • exclude
  • returns
  • parameters
  • parameter

Source: expectTypeOf | Vitest. Checked 2026-11-03.