title: Difference between Readonly<[]> and ReadOnlyArray<>
body: <p><strong>Code 1:</strong></p>
  
  <pre><code> let readonlyArray: ReadonlyArray&lt;string | number&gt; = ["test", 1, 1];
  </code></pre>
  
  <p><strong>Code 2:</strong></p>
  
  <pre><code>let readonlyArray: Readonly&lt;[string, number]&gt; = ["test", 1, 1];
  </code></pre>
  
  <p>Both lines of code seem to do similar things. I don't know what is the difference between declaring array as <code>ReadOnly</code> and <code>ReadOnlyArray</code>.</p>
  
  <p>Also, which one is  best for performance and why? </p>