Is there a better way to do optional function parameters in JavaScript? [duplicate]

Answer 1

With ES2015/ES6 you can take advantage of Object.assign which can replace $.extend() or _.defaults()

function myFunc(requiredArg, options = {}) {
  const defaults = {
    message: 'Hello',
    color: 'red',
    importance: 1
  };

  const settings = Object.assign({}, defaults, options);

  // do stuff
}

You can also use defaults arguments like this

function myFunc(requiredArg, { message: 'Hello', color: 'red', importance: 1 } = {}) {
  // do stuff
}