es6常用语法

ES6常用语法

1. let const 
/* let 和 const
    需要改变的变量用let 
*/
let foo = 'aa'
const cc = '234'

/* 2.模板字符串 */
let str = `aaa${foo}`

/* 3.箭头函数 */

setTimeout(() => {
    
}, timeout);

/* 4. 结构赋值 */

const obj = {age:13,name:'xxx'}
let { age }  = obj
age // 13

/* 5. 扩展运算符 ... */

// 合并数组
const arr1 = ['a', 'b'];
const arr2 = ['c'];
const arr3 = ['d', 'e'];
// ES6 的合并数组
[...arr1, ...arr2, ...arr3]

// [...'hello']
// [ "h", "e", "l", "l", "o" ]

/* 6. Promise */

const promise = new Promise(function (resolve, reject) {
    if (true) {
        resolve('value')
    } else {
        reject('error')
    }
})

promise.then(res => {
    //成功
}).catch(err => {
    //失败
})

const p1 = new Promise(function(resolve,reject){

})

const p2 = new Promise(function(resolve,reject){

})

const alls =  Promise.all([p1,p2]).then(res=>{
    [res]
})


/* 7. async await*/

async function asyncPrint(value, ms) {
    await timeout(ms);
    console.log(value);
  }