Dependency was not found vue.js

I am trying to make an calendar with vue and firebase, an i got this error:

This dependency was not found:

* @main.js in ./node_modules/cache-loader/dist/cjs.js??ref--12-0!./node_modules/babel-loader/lib!./node_modules/cache-loader/dist/cjs.js??ref--0-0!./node_modules/vue-loader/lib??vue-loader-options!./src/components/Calendar.vue?vue&type=script&lang=js&

To install it, you can run: npm install --save @main.js

Hope you can help me

<script>
import{db} from '@main.js';
export default {
    name:'Calendar',
    data: ()=> ({
        today: new Date().toISOString().substring(0,10),
        focus: new Date().toISOString().substring(0,10),
        type:"month",
        typeToLabel:{
            month:"Month",
            week:"Week",
            day:"Day",
            "4day":"4Days"
............

this is the part where th compilier goes to if i click on the error and he shows

Could not find a declaration file for module './index'. 'd:/Test/alpha/node_modules/cache-loader/dist/index.js' implicitly has an 'any' type.ts(7016)

"use strict";

module.exports = require('./index');