Truthiness

Truthiness might not be a word you’ll find in the dictionary, but it’s very much something you’ll hear about in JavaScript.

In JavaScript, we can use any expression in conditionals, &&s, ||s, if statements, Boolean negations (!), and more. As an example, if statements don’t expect their condition to always have the type boolean.

function getUsersOnlineMessage(numUsersOnline: number) {
  if (numUsersOnline) {
    return `There are ${numUsersOnline} online now!`;
  }

  return "Nobody's here. :(";
}

Learn more from the following links:

• Truthiness Narrowing