title: complex types in typescript
body: <p>I need to describe in my interface a string with indexes also in the end of string can be work or crash:</p>
  <pre><code>export interface Test {
      date: string,
     'stat.conv[index: number].key[index: number].(work || crash)': Test2[]
  }
  </code></pre>
  <p>Is this possible in typescript?</p>