vue-progressbar in vuex typeError

I've just started to learn vue and vuex.

I want to use the progressbar from this link

Like the description said I imported the main.js file into my actions.js

import app from '../../../main'  //This is causing the error

so I could use this just before my axios-request:

 app.$Progress.start()

The main.js file:

try {
    window.$ = window.jQuery = require('jquery');
    window.Popper = require('popper.js').default;
    window._ = require('lodash')

    require('admin-lte');
    require('bootstrap')
} catch (e) {}

import Vue from 'vue'
import App from './App.vue'
import router from './router'
import store from './store/index'
import VueProgressBar from 'vue-progressbar'
import swal from 'sweetalert2'
import moment from 'moment'

Vue.config.productionTip = false

Vue.use(VueProgressBar, {
    color: 'rgb(143,255,199)',
    failedcolor: 'red',
    height: '5px'
})

Vue.use(require('vue-moment'))
Vue.use(moment)

window.bus = new Vue()
window.swal = swal;

const toast = swal.mixin({
    toast: true,
    position: 'top-end',
    showConfirmButton: false,
    timer: 3500
})

window.toast = toast

export default new Vue({
    router,
    store,
    render: h => h(App)
}).$mount('#app')

This is working, but I'm getting errors when working on those pages.

( "TypeError: _main__WEBPACK_IMPORTED_MODULE_1__.default is undefined")

Edit: Updated the main.js file

So my question is how do I fix this?