[Vuejs]-Laravel 6 + Vue.js Failed to mount component: template or render function not defined

This might help you to solve your problem, if not just tell me to find new solution. first remove this in your app.js

const files = require.context('./', true, /\.vue$/i)
files.keys().map(key => Vue.component(key.split('/').pop().split('.')[0], files(key).default))

Next, remove also this code, you already imported vue twice.

import Vue from 'vue'