import api from '@/js/api'
Vue.prototype.$api = api

//api.js
import Vue from 'vue'

export default function () {
   console.log('default export', this)
   //=> Vue
}

var MyModule = {
    this.fn1 = function(){console.log(this) //=>Vue}
    this.fn1 = function(){console.log(this) //=>Vue}
}