Babel can't properly extend Array?
<p>I am trying to extend the Array in native JS. But not just modifying the prototype. I thought I'd give it a shot with the new <code>class</code> es2015 syntax.</p>

<p>Trying it out native (chrome already supports it - yay ヽ(´▽｀)ノ) and it all works just fine. Switching over to Babel for better support, it stops working. After trying a bit, I saw, that none of the methods are available on the new Object. Test code:</p>

<pre><code>class CustomList extends Array {
  constructor(...elms) {
    super(...elms);

    this.testprop = "test";
  }

  customMethod(a) {
    console.log(a, this);
  }
}
</code></pre>

<p><a href="https://babeljs.io/repl/#?babili=false&amp;evaluate=true&amp;lineWrap=false&amp;presets=es2015%2Creact%2Cstage-2&amp;experimental=true&amp;loose=true&amp;spec=false&amp;playground=false&amp;code=class%20CustomList%20extends%20Array%20%7B%0A%20%20constructor(...elms)%20%7B%0A%20%20%20%20super(...elms)%3B%0A%20%20%20%20%0A%20%20%20%20this.testprop%20%3D%20%22test%22%3B%0A%20%20%7D%0A%20%20%0A%20%20customMethod(a)%20%7B%0A%20%20%20%20console.log(a%2C%20this)%3B%0A%20%20%7D%0A%7D%0A%0Alet%20list%20%3D%20new%20CustomList(1%2C2%2C3)%3B%0A%0Aconsole.log(list%20instanceof%20CustomList)%3B%0A%0Aconsole.log(list.customMethod%2C%20list.testprop)%3B%0A%0A%0A%2F%2F%20produces%20%22list.customMethod%20is%20not%20a%20function%22%20error%0A%2F%2F%20list.customMethod(%22test%22)%3B%0A%0Aconsole.log(%22%5Cn%5Cn%5Cn%22)" rel="nofollow">(test in babel)</a></p>