title: How to validate Date object through io-ts (typescript)?
body: <p>I haven't been able to find documentation on this, so here I am StackOverflow.</p>
  <p>I have an interface that I want to convert and use in io-ts' run-time validation. This interface includes a field with type <code>Date</code> on it. I've looked through the rest of the commands on <code>t</code> when importing <code>io-ts</code> as <code>t</code> and I can't find a way to validate that it's a date</p>
  <p>Ex:</p>
  <pre><code>export interface Transaction {
    transactionDate: Date,
    phrase: string
  }
  </code></pre>
  <p>How do I convert this into a type using io-ts? Ideally it would be something like this</p>
  <pre><code>export const Transaction = t.type({
    transactionDate: t.date,
    phrase: t.string
  })
  </code></pre>
  <p>The only thing that I've found that works is setting the Date as type <code>t.string</code>, but that would let any kind of string through.</p>