Vue（ES6）导出变量、常量、方法
lib.js
let bar = '彭于晏'
const isTestServer = true
let fn = function () {
console.log('有梦想的咸鱼')
}
export { bar, isTestServer, fn }
main.js
import { bar, isTestServer, fn } from './lib'
console.log(bar)
console.log(isTestServer)
console.log(fn)
