43. Array Comprehension (Array内包表記)
var arr1 = [for (i of [1, 2, 3]) i * i];
//=> [1, 4, 9]
var arr2 = [
for (x of ["A", "B"])
for (y of [0, 1, 2, 4])
x + '' + y ];
//=> ["A0", "A1", "A2", "A4", "B0", "B1", "B2", "B4"]
http://jsbin.com/qupex/2/edit?js,console
配列がイテレーションで作れるよ
44. Destructuring Assignment(デストラクチャリング)分配束縛
var goku = 10000, ginyu = 5000;
値の交換!
var [goku, ginyu] = [ginyu, goku];
console.log([goku, ginyu]);//=>[5000, 10000]
var saiyajin = {gohan: 10000, bejita: 8000};
var {gohan, bejita} = saiyajin;
console.log([gohan, bejita]);//=>[10000, 8000]
Objectプロパティから変数設定!
変数値の交換やオブジェクトの値を変数に設定したりできます。