1-1 export
Tips:使用export导出需要加{}
//a.js 导出var a = 100;var b = 200;export {a,b}
//b.js导入import {a,b} from "./a.js"
1-2 export default
Tips:export default在每一个模块中只能有一个
var a = 100;var b = 200;export default {a,b}
//b.jsimport sum from "./a.js"
Tips:导入的时候,不能解构 import {a} from “./a.js”失效
