[vue2] Introduce jquery into vue2

If the following three steps are done well, the problem of jquery is not define will not appear

Install

npm i jquery -S

Referenced in main.js

import $ from 'jquery'
Vue.prototype.$ = $

Modify webpack configuration

In the build directory: build/ webpack.base.conf.js

//webpack.base.conf.js

//一定要先定义webpack变量，否则报错webpack not define
const webpack = require('webpack');

module.exports = {
    
    
	plugins: [
	    new webpack.optimize 
	    	.CommonsChunkPlugin('common.js'),
	    new webpack.ProvidePlugin({
    
    
	      jQuery: "jquery",
	      $: "jquery"
	    })
	  ]
}