es6 Javascript class using this inside a callback
<p>The new es6 class allows you to use the self reference variable <code>this</code> inside methods.<br/>
However if a class method has a sub function or a callback, that function/callback no longer has access to the self reference variable <code>this</code><br/></p>

<pre><code>class ClassName {
  constructor(dir){
    this.dir = dir;
    fs.access(this.dir, fs.F_OK | fs.W_OK, this.canReadDir);//nodejs fs.access with callback
  }

  canReadDir(err){
    this.dir;// NO ACCESS to class reference of this
  }
  //OR
  aMethod(){
    function aFunc(){
      this.dir;// NO ACCESS to class reference of this
    }
  }
}
</code></pre>

<p>Is there any solution to this?</p>