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/**
 * JS + ES6 - Buit-in types.
 *
 * There are 6 built-in types in JavaScript (undefined, string, number, boolean, null, object). Plus, a new one
 * introduced with ES6 (symbol).
 **/
var foo;
console.log(typeof foo); // "undefined"

var bar = 'P. Nutt';

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/**
 * ES6 - Destructuring assignment
 **/
var [person1, person2, person3, ...otherPeople] = [
    {
        name: 'P. Nutt',
        age: 18
    },
    {
        name: 'Hazel Nutt',

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/**
 * ES6 - Default function parameters.
 *
 * Define default value for empty function parameters.
 **/
function sayHello(name, isPirate = false) {
    if (isPirate) {
        console.log(name + ' says: Arrr! This be good grog!'); // Manny Bones says: Arrr! This be good grog!
    } else {
        console.log(name + ' says: Hi, how are you?'); // P. Nutt says: Hi, how are you?

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/**
 * ES6 - Arrow functions.
 *
 * Empty arrow functions return `undefined`. The same as normal functions.
 **/
let emptyness = () => {};
console.log(emptyness()); // undefined
var completelyEmpty = function() {

};

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/**
 * ES6 - Arrow functions.
 *
 * Arrow functions don't rebind `this`. Comparison between old `function` approach and `arrow function` approach.
 **/
function Person0(name, age) {
    this.name = name;
    this.age = age;

    setTimeout(function() {

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/**
 * Difference between implicit and explicit global variables
 **/
var myGlobal1 = 'P. Nutt';
myGlobal2 = 'Hazel Nutt';
delete myGlobal1; // false
delete myGlobal2; // true
console.log(myGlobal1); // P. Nutt
console.log(myGlobal2); // ReferenceError

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/**
 * ES6 - Arrow functions.
 *
 * Arrow functions are always anonymous. Useful for one line callbacks.
 **/
const people = [
    {
        name: 'P. Nutt',
        age: 18
    },

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/**
 * ES6 - var, let, const. The temporal dead zone.
 *
 * According to ECMAScript 6 specification. https://tc39.github.io/ecma262/#sec-let-and-const-declarations
 * let and const declarations define variables that are scoped to the running execution context's
 * LexicalEnvironment. The variables are created when their containing Lexical Environment is instantiated but may
 * not be accessed in any way until the variable's LexicalBinding is evaluated. A variable defined by a
 * LexicalBinding with an Initializer is assigned the value of its Initializer's AssignmentExpression when the
 * LexicalBinding is evaluated, not when the variable is created. If a LexicalBinding in a let declaration does
 * not have an Initializer the variable is assigned the value undefined when the LexicalBinding is evaluated.