Function toBeUndefined

packages/expect/src/matchers.ts:446–463

(received: unknown, expected: void)

  },

  toBeUndefined(received: unknown, expected: void) {
    const matcherName = 'toBeUndefined';
    const options: MatcherHintOptions = {
      isNot: this.isNot,
      promise: this.promise,
    };
    ensureNoExpected(expected, matcherName, options);

    const pass = received === void 0;

    const message = () =>
      // eslint-disable-next-line prefer-template
      matcherHint(matcherName, undefined, '', options) +
      '\n\n' +
      `Received: ${printReceived(received)}`;

    return {message, pass};
  },

  toContain(received: ContainIterable | string, expected: unknown) {
    const matcherName = 'toContain';