vue.config.js

const webpack = require('webpack');

// used in vue cli 3
module.exports = {
  configureWebpack: {
    resolve: {
      extensions: ['.js'],
      alias: {
        'jquery': 'jquery/dist/jquery.min',
      }
    },
    plugins: [
      new webpack.ProvidePlugin({
        $: 'jquery',
        jquery: 'jquery',
        'window.jQuery': 'jquery',
        jQuery: 'jquery'
      })
    ]
  },
};