Function cb

lib/internal/test_runner/utils.js:81–102

(err)

  let calledCount = 0;
  const { promise, resolve, reject } = PromiseWithResolvers();
  const cb = (err) => {
    calledCount++;

    // If the callback is called a second time, let the user know, but
    // don't let them know more than once.
    if (calledCount > 1) {
      if (calledCount === 2) {
        throw new ERR_TEST_FAILURE(
          'callback invoked multiple times',
          kMultipleCallbackInvocations,
        );
      }

      return;
    }

    if (err) {
      return reject(err);
    }

    resolve();
  };

  return { __proto__: null, promise, cb };
}