ES2015 (ES6)についてのまとめ ref: http://qiita.com/tuno-tky/items/74ca595a9232bcbcd727

file0.txt

let foo = [1, 2, 3];
{
  let foo = [4, 5, 6];
  console.log(foo);
  // => 4, 5, 6
}
console.log(foo);
// => 1, 2, 3

file1.txt

{
  const PI = 3.14;
  const circleArea = function (radius) {
    return radius * radius * PI;
  };
  console.log(circleArea(3));
  // => 28.26
  // ここでPI = 3.1415;のような再代入を行おうとすると、例外が発生する
}
console.log(PI);
// => undefined

file10.txt

var name = Izmeal;
var age  = 21;

file11.txt

var [name, age] = ['Koyabu', 20];

file12.txt

var array = [1, 2, 3]
function f(x, y, z) { }
f(...array);
//f(1, 2, 3)という引数での関数fの呼び出しと同義

[...array, 4, 5, 6]
//[1, 2, 3, 4, 5, 6]となる
var x
var y
var z
var variables = [x, y, z]
[a, b, ...variables] = [1, 2, 3, 4, 5];
// a = 1, b = 2, x = 3, y = 4, z = 5とした場合と同じ

file13.txt

function f(x, ...ys) {
    console.log(x, ys);
}
f(2, 3, 5);
//=> 2 [ 3, 5 ]

file14.txt

function multiply(a, b = 1) {
  return a*b;
}
multiply(5); // 5

file15.txt

var name = 'Koyabu'

var hello = `My name is
${name}`
console.log(hello)
//=>My name is 
//Koyabu

file2.txt

function Human(name) {
  this.name = name;
}

Human.prototype.hello = function () {
  console.log('My name is ' + this.name);
};

file3.txt

obj = new Human('Izmeal')
obj.hello
//=> 'My name is Izmeal' 

file4.txt

class Human {
  constructor(name) {
    this.name = name;
  }
  hello() {
    console.log('My name is ' + this.name);
  }
}

file5.txt

obj = new Human('Koyabu')
obj.hello
//=> 'My name is Koyabu'

file6.txt

class Human {
  constructor(name) {
    this.name = name;
  }
  hello() {
    console.log('My name is ' + this.name);
  }
  static num_of_hands() {
    console.log(2)
  }
}

Human.num_of_hands()
//=> 2

file7.txt

class Animal { 
  constructor(name) {
    this.name = name;
  }

  speak() {
    console.log(this.name + ' makes a noise.');
  }
}

class Dog extends Animal {
  speak() {
    console.log(this.name + ' barks.');
  }
}

file8.txt

// 従来のfunctionを使った書き方
var plus = function(x, y) {
  return x + y;
};

// アロー関数
let plus = (x, y) => {
  return x + y;
};

// 単一式の場合はブラケットやreturnを省略できる
let plus = (x, y) => x + y;

file9.txt

var func = () => ({ foo: 1 });）