Un résumé commun des extensions JavaScript ES6 aux tableaux, fonctions et objets

let arrayLike = {

    '0': 'a',

    '1': 'b',

    '2': 'c',

    length: 3};

// ES5的写法var arr1 = [].slice.call(arrayLike); // ['a', 'b', 'c']

// ES6的写法let arr2 = Array.from(arrayLike); // ['a', 'b', 'c']

Array.from([1, 2, 3])

// [1, 2, 3]

Array.from('hello')

// ['h', 'e', 'l', 'l', 'o']

Array.from(arrayLike, x => x * x);

// 等同于Array.from(arrayLike).map(x => x * x);

 

Array.from([1, 2, 3], (x) => x * x)

// [1, 4, 9]

Array.of(3, 11, 8) // [3,11,8]

Array.of(3) // [3]

Array.of(3).length // 1

for (let index of ['a', 'b'].keys()) {

  console.log(index);

}

// 0// 1

for (let elem of ['a', 'b'].values()) {

  console.log(elem);

}

// 'a'// 'b'

for (let [index, elem] of ['a', 'b'].entries()) {

  console.log(index, elem);

}

// 0 "a"// 1 "b"

function log(x, y = 'World') {

  console.log(x, y);}

log('Hello') // Hello World

log('Hello', 'China') // Hello China

log('Hello', '') // Hello

function foo(x = 5) {

  let x = 1;

 // error

  const x = 2; 

// error

}

// ES5[1, 2].concat(more)

// ES6[1, 2, ...more]

var arr1 = ['a', 'b'];var arr2 = ['c'];var arr3 = ['d', 'e'];

// ES5的合并数组

arr1.concat(arr2, arr3);

// [ 'a', 'b', 'c', 'd', 'e' ]

// ES6的合并数组

[...arr1, ...arr2, ...arr3]

// [ 'a', 'b', 'c', 'd', 'e' ]

$(function() {

       var a=()=>{

         const [a, b, c, d, e] = 'hello';

            console.log(a++b++c++d++e);

       }

        a();//不带参数

//h__e__l__l__o

    var b=(name,password)=>{

         

            console.log("用户名："+name+",密码："+password);

       }

      b("张三","123456");//带参数

//用户名：张三,密码：123456

        });