Function assertIsCallbackFunction

testing/time.ts:130–139

(
  callback: unknown,
  fnName: "setTimeout" | "setInterval",
)

let time: FakeTime | undefined = undefined;

function assertIsCallbackFunction(
  callback: unknown,
  fnName: "setTimeout" | "setInterval",
): asserts callback is (...args: unknown[]) => void {
  if (typeof callback !== "function") {
    throw new TimeError(
      `FakeTime does not support non-function callbacks to ${fnName}`,
    );
  }
}

function fakeSetTimeout(
  callback: string | ((...args: unknown[]) => unknown),