Typescript has unions, so are enums redundant? : <p>Ever since TypeScript introduced unions types, I wonder if there is any reason to declare an enum type. Consider the following enum type declaration:</p>

<pre><code>enum X { A, B, C }
var x:X = X.A;
</code></pre>

<p>and a similar union type declaration:</p>

<pre><code>type X: "A" | "B" | "C"
var x:X = "A";
</code></pre>

<p>If they basically serve the same purpose, and unions are more powerful and expressive, then why are enums necessary?</p>
