export与import

（一）export一个方法
export

export function formatDate () {
  console.log('我是引入的数据')
}

import

import { formatDate } from '@/assets/js/time/formatDate'

formatDate()

（二）export类
export

export class FormatDate {
  cc () {
    console.log('123')
  }
}

import

import { FormatDate } from '@/assets/js/time/formatDate'

let Fmt = new FormatDate()
Fmt.cc()