title: Typesrcript typing {[key: string]: any}
body: <p>I have this function: </p>
  
  <pre><code>validate(formGroup: FormGroup): {[key: string]: any} 
  </code></pre>
  
  <p>and I can </p>
  
  <pre><code>return {validateLocation: false}
  </code></pre>
  
  <p>or</p>
  
  <pre><code>return {'validateLocation': false}
  </code></pre>
  
  <p><code>key:string</code> shoud be <code>'validateLocation': false</code>, why both are all working? validateLocation is NOT string, right?</p>