Switch statement

export function hey(message) {
  const speech = message.trim();
  if (speech == '') {
    return 'Fine. Be that way!';
  }

  const isQuestion = speech.endsWith('?');
  const isShout = /[A-Z]{1}/.test(speech) && speech == speech.toUpperCase();

  switch (true) {
    case isQuestion && isShout:
      return "Calm down, I know what I'm doing!";
    case isShout:
      return 'Whoa, chill out!';
    case isQuestion:
      return 'Sure.';
    default:
      return 'Whatever.';
  }
}

In this approach you use a switch statement to test if there is a question or a shout. The switch returns the right response for a question, shout, shouted question, or for not being a shout or question.

The String trimEnd method is applied to the input to eliminate any whitespace at the end of the input. If the string has no characters left, it returns the response for saying nothing.

The first half of the shout condition

/[A-Z]{1}/.test(speech);

is constructed from a regular expression pattern to ensure there is at least one uppercase letter character in the String. This is because the second half of the condition tests that the uppercased input is the same as the input. If the input were only "123" it would equal itself uppercased, but without letters it would not be a shout.

The uppercasing is done by using the String method toUpperCase.

The isQuestion and isShout values are tested in a switch. If neither isQuestion and isShout are true, the default arm of the switch returns the response when the input is neither a question nor a shout.

Shortening

Note that when the body of an if statement is a short single line, both the test expression and the body could be put on the same line, like so

if (input == '') return 'Fine. Be that way!';

It may not comply with some coding styles, but your team preferences may allow it.