spikesagal

function mixin() {
    return JSON.parse('{'
        + [].reduce.call(arguments, function (prev, cur) {
            var str = JSON.stringify(cur);
            if (!str || str.slice(0, 1) !== '{' || str.slice(-1) !== '}') {
                throw new Error('Invalid object: ' + str);
            }
            return (prev ? prev + ',' : '')
            + str.slice(1, -1);
        }, null)

spikesagal

'use strict';
class Person {
  constructor(arg = {
    firstName: 'John',
    lastName: 'Doe'
  }) {
    ({
      firstName: this.firstName = '<FIRSTNAME_UNKNOWN>',
      lastName: this.lastName = '<LASTNAME_UNKNOWN>'
    } = arg);

spikesagal

(function IIFE() {
  'use strict';
  function counter() {
    this.def = 0;
    return (function() {
      return this.def++;
    }).bind(this);
  };
  var obj = {};
  Object.defineProperties(obj, {

spikesagal

(function IIFE() {
  'use strict';
  var obj = {};
  Object.defineProperties(obj, {
    counter: {
      get: (function IIFE() {
        var def = 0;
        return function() {
          return def++;
        }