ES6语法（十三）module

在ES6之前，JS文件之间的导入、导出是需要借助require.js、sea.js。现在，可以使用import、export来实现原生JavaScript的导入、导出了。
export
1.导出变量或者常量

export const name = 'hello'
export let addr = 'Beijing'
export var list = [1, 2, 3]

或者

const name = 'hello3'
let addr = 'Beijing'
let list = [1, 2, 4]

export default name
export {
  addr,
  list
}

2.导出函数

export function say(content) {
  console.log(content)
}
export function run() {
  console.log('i am running')
}

或者

const say = (content) => {
  console.log(content)
}
const run = () => {
  console.log('i am running')
}
export {
  say,
  run
}

3.导出Object

export ({
	code: 0,
	message: 'success'
})

或者

const des = {
  age: 20,
  addr: 'Beijing'
}
export default {
  des
}

4.导出Class

class Test{
	constructor(){
		this.id = 2
	}
}
export{
	Test
}

或者

export class Test {
  constructor () {
    this.id = 6
  }
}

5.修改导出名称

const name = 'hello'
let addr = 'Chengdu City'
var list = [1,2,3]
export{
	name as cname,
	addr as caddr,
	list
}

6.设置默认导出

const name = 'hello'
let addr = 'Chengdu City'
var list = [1,2,3]
export{
	name as cname,
	addr as caddr
}
export default list

import
1.直接导入
假设导出模块A是这样的：

const name = 'hello'
let addr = 'Chengdu City'
var list = [1,2,3]
export{
	name as cname,
	addr as caddr
}
export default list

则导入：

import list, {cname, caddr} from A

2.修改导入名称

import list, { cname as name, caddr } from A

3.批量导入

import list, * as mod from A
console.log(list)
console.log(mod.cname)
console.log(mod.caddr)