title: what is T.Type in swift
body: <p>Can anyone tell me what is <code>T.Type</code> when I use <code>JSONDecoder().decode()</code>?</p>
  <p>I think it is type to decode data what I encoded.</p>
  <p>So many example use above method like this:</p>
  <pre><code>JSONEncoder().decode([People].self, from: data)
  </code></pre>
  <p>If I check that method's definition I can see <code>T.Type</code>.</p>
  <p>I know the generics but what is <code>T.Type</code>?</p>
  <p>What's the difference between just <code>T</code> and <code>T.Type</code>?</p>
  <p>when we declare some variables, we allocated their types like this</p>
  <p><code>var someValue: Int</code>
  , not <code>var someValue: Int.self</code></p>
  <p>What is the <code>T.Type</code> exactly and <code>Type.self</code>?</p>