title: npm run dev not working
body: <p>I have a problem with vueJs webpack, I want to run on the server, with a command: npm run dev. But I get some error message as below.</p>
  
  <p>Could anyone tell me how do I solve it?? Thank you very much!</p>
  
  <p>Error message</p>
  
  <blockquote>
    <p>npm ERR! code EJSONPARSE</p>
    
    <p>npm ERR! Failed to parse json</p>
    
    <p>npm ERR! Unexpected token / while parsing '{</p>
    
    <p>npm ERR!   "name": "vue-loader-demo",</p>
    
    <p>npm ERR!   "versio'</p>
    
    <p>npm ERR! File: /Users/sylvia/Documents/FE/Practice/vue/vue-loader-</p>
    
    <p>demo/package.json</p>
    
    <p>npm ERR! Failed to parse package.json data.</p>
    
    <p>npm ERR! package.json must be actual JSON, not just JavaScript.</p>
    
    <p>npm ERR! 
    npm ERR! Tell the package author to fix their package.json file. </p>
    
    <p>JSON.parse</p>
    
    <p>npm ERR! A complete log of this run can be found in:</p>
    
    <p>npm ERR!     /Users/sylvia/.npm/_logs/2018-04-17T12_39_56_372Z-debug.log</p>
  </blockquote>
  
  <p>Here is the package.json</p>
  
  <pre><code>{
   "name": "vue-loader-demo",
   "version": "1.0.0",
   "description": "",
   "main": "main.js",
   "scripts": {
      "build": "webpack",
      "dev": "webpack-dev-server --devtool eval --progress --colors --hot" 
    },
    "author": "",
    "license": "ISC",
    "dependencies": {
      "webpack": "^4.5.0",
      "webpack-dev-server": "^3.1.3"
    }
  }
  </code></pre>
  
  <p>webpack.config.js</p>
  
  <blockquote>
    <p>module.exports={</p>
    
    <p>entry:'./main.js',</p>
    
    <p>output:{</p>
  
  <pre><code> path:_dirname，
  
   filename:‘'bundle.js'’
  </code></pre>
    
    <p>}
    }</p>
  </blockquote>
  
  <p>File structure</p>
  
  <blockquote>
    <p>|-index.html</p>
    
    <p>|-main.js    </p>
    
    <p>|-App.vue   </p>
    
    <p>|-package.json  </p>
    
    <p>|-webpack.config.js  </p>
  </blockquote>