Function spy

testing/mock.ts:943–967

(
  funcOrConstOrSelf?:
    | ((this: Self, ...args: Args) => Return)
    | (new (...args: Args) => Self)
    | Self,
  property?: keyof Self,
)

  GetReturnFromProp<Self, Prop>
>;
export function spy<
  Self,
  Args extends unknown[],
  Return,
>(
  funcOrConstOrSelf?:
    | ((this: Self, ...args: Args) => Return)
    | (new (...args: Args) => Self)
    | Self,
  property?: keyof Self,
): SpyLike<Self, Args, Return> {
  if (!funcOrConstOrSelf) {
    return functionSpy<Self, Args, Return>();
  } else if (property !== undefined) {
    return methodSpy<Self, Args, Return>(funcOrConstOrSelf as Self, property);
  } else if (funcOrConstOrSelf.toString().startsWith("class")) {
    return constructorSpy<Self, Args>(
      funcOrConstOrSelf as new (...args: Args) => Self,
    );
  } else {
    return functionSpy<Self, Args, Return>(
      funcOrConstOrSelf as (this: Self, ...args: Args) => Return,
    );
  }
}

/** An instance method replacement that records all calls made to it. */
export interface Stub<