title: Typescript: how to type variadic arguments?
body: <p>Trying to convert this function to typescript:</p>
  <pre><code>const runProcess = (...proc) =&gt; {
    const proc = child_process.spawn(...proc, {
      stdio: [&quot;ignore&quot;, &quot;pipe&quot;, &quot;pipe&quot;],
    });
  </code></pre>
  <p>Can it be done? In this particular case, procs can be either a single string or a 2-tuple (how to represent this in TS?) made up of a string and an array of strings.</p>