title: how to config grunt.js to minify files separately
body: <p>there are some js files in static/js/</p>
  
  <pre><code>    1. a.js
      2. b.js
      3. c.js   
  </code></pre>
  
  <p>how to config grunt.js to get below files:</p>
  
  <pre><code>    1. a.min.js
      2. b.min.js
      3. c.min.js
  </code></pre>
  
  <p>as far, I have to type specific file name:</p>
  
  <pre><code>  min: {
      dist: {
      src:  'js/**/*.js',
      dest: 'js/min/xxx.min.js'
     }
   }
  </code></pre>