Function spyOn

test/transferables.test.ts:12–17

(
  target: ((...args: Args) => OriginalReturn),
  spy: SpyInit<Args, OriginalReturn, NewReturn>
)

const arrayBufferPlaceholder = Symbol("ArrayBufferPlaceholder")

function spyOn<Args extends any[], OriginalReturn, NewReturn>(
  target: ((...args: Args) => OriginalReturn),
  spy: SpyInit<Args, OriginalReturn, NewReturn>
): (...args: Args) => NewReturn {
  return spy(target)
}

function replaceArrayBufferWithPlaceholder<In extends any>(obj: In, arrayBuffer: ArrayBuffer): In extends ArrayBuffer ? (In | typeof arrayBufferPlaceholder) : In {
  if ((obj as any) === arrayBuffer) {