Function expectedException

lib/assert.js:469–575

(actual, expected, message, fn)

}

function expectedException(actual, expected, message, fn) {
  let generatedMessage = false;
  let throwError = false;

  if (typeof expected !== 'function') {
    // Handle regular expressions.
    if (isRegExp(expected)) {
      const str = String(actual);
      if (RegExpPrototypeExec(expected, str) !== null)
        return;

      if (!message) {
        generatedMessage = true;
        message = 'The input did not match the regular expression ' +
                  `${inspect(expected)}. Input:\n\n${inspect(str)}\n`;
      }
      throwError = true;
      // Handle primitives properly.
    } else if (typeof actual !== 'object' || actual === null) {
      const err = new AssertionError({
        actual,
        expected,
        message,
        operator: 'deepStrictEqual',
        stackStartFn: fn,
        diff: this?.[kOptions]?.diff,
      });
      err.operator = fn.name;
      throw err;
    } else {
      // Handle validation objects.
      const keys = ObjectKeys(expected);
      // Special handle errors to make sure the name and the message are
      // compared as well.
      if (expected instanceof Error) {
        ArrayPrototypePush(keys, 'name', 'message');
      } else if (keys.length === 0) {
        throw new ERR_INVALID_ARG_VALUE('error',
                                        expected, 'may not be an empty object');
      }
      if (isDeepEqual === undefined) lazyLoadComparison();
      for (const key of keys) {
        if (typeof actual[key] === 'string' &&
            isRegExp(expected[key]) &&
            RegExpPrototypeExec(expected[key], actual[key]) !== null) {
          continue;
        }
        compareExceptionKey(actual, expected, key, message, keys, fn);
      }
      return;
    }
  // Guard instanceof against arrow functions as they don't have a prototype.
  // Check for matching Error classes.
  } else if (expected.prototype !== undefined && actual instanceof expected) {
    return;
  } else if (ObjectPrototypeIsPrototypeOf(Error, expected)) {
    if (!message) {
      generatedMessage = true;