title: I want to automatically delete comments when building with webpack
body: <p><strong>I want to automatically delete comments when building with webpack.</strong></p>
  
  <p>・ I want to delete comments after //</p>
  
  <p>・Can I delete comments by setting some options?</p>
  
  <p>・how can I do?</p>
  
  <hr>
  
  <p>▼main.js</p>
  
  <pre><code>// src/main.js　I want to delete this part
  var m = require("mithril")
  
  var UserList = require("./views/UserList")
  
  m.mount(document.body, UserList)
  //I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.I want to delete this part.
  </code></pre>
  
  <hr>
  
  <p>▼package.json</p>
  
  <pre><code> "scripts": {
       "build": "webpack src/index.js bin/main.js -p"
   }
  </code></pre>
  
  <hr>
  
  <pre><code>$ npm start
  </code></pre>