es6

'use strict';
let numbers = [1, 2, 3, 4, 5, 6, 7, 8, 9];


// 除去取余2的 - es6
let es5OddNumbers = numbers.filter(function (number) {
    return number % 2;
});
console.log(es5OddNumbers);

//  除去取余2的 - es6 - 第二种写法
let es6OddNumbers = numbers.filter(number => number % 2);
console.log(es6OddNumbers);



// 和es5不一样的函数返参
let square = x => x * x;
console.log(square(10));

// let add = (形参1,形参2,...)
let add = (a, b) => a + b;
console.log(add(3, 4));

// 数组对象
let developers = [{ name: 'Rob' }, { name: 'Jake' }];
// 回调拿出name
let es5Output = developers.map(function (developer) {
    return developer.name;
});
console.log(es5Output);

let es6Output = developers.map(developer => developer.name);
console.log(es6Output);



// es5 倒计时
function CounterES5() {
    this.seconds = 0;
    window.setInterval(function () {
        this.seconds++;
    }.bind(this), 1000); // or }.bind(this), 1000) and skip that = this
}
var counterA = new CounterES5();
window.setTimeout(function () {
    console.log(counterA.seconds);
}, 1200);

// es6倒计时
function CounterES6() {
    this.seconds = 0;
    window.setInterval(() => this.seconds++, 1000);
}

let counterB = new CounterES6();
window.setTimeout(() => console.log(counterB.seconds), 1200);