handy ES6

gistfile1.txt

//Optional Default params
//es6
function myFunc({name = 'Default user', age = 'N/A'} = {}) {

}

//es5 via babeljs.io
'use strict';

function myFunc() {
  var _ref = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : {},
      _ref$name = _ref.name,
      name = _ref$name === undefined ? 'Default user' : _ref$name,
      _ref$age = _ref.age,
      age = _ref$age === undefined ? 'N/A' : _ref$age;
}

//es5 
function myFunc() {
  var opts = arguments[0] === undefined ? {} : arguments[0];
  var name = opts.name === undefined ? 'Default user' : opts.name;
  var age = opts.age === undefined ? 'N/A' : opts.age;
}