Javascript Array operations on string-index array : <p>It seems like <code>map</code>, <code>forEach</code>, <code>filter</code> and this sort of operators don't work with string-indexed arrays like so:</p>

<pre><code>let a = [];
a['first element'] = 1;
a['second element'] = 2;
a['third element'] = 3;
a.forEach(console.log)
//undefined
</code></pre>
