title: Extend a String class in ES6
body: <p>I can write the following in ES5:</p>
  
  <pre><code>String.prototype.something=function(){
    return this.split(' ').join('');
  };
  </code></pre>
  
  <p>How do I do the same thing in ES6 using the new features?</p>
  
  <p>I know that this is also a valid ES6. I want to know whether there's any other way of implementing such functions in ES6 which is shorter?<br>
  The above function is just an example.</p>