title: How to update object in React state
body: <p>I have an indexed list of <code>users</code> in the JS object (not array). It's part of the React state.</p>
  
  <pre><code>{
      1: { id: 1, name: "John" }
      2: { id: 2, name: "Jim" }
      3: { id: 3, name: "James" }
  }
  </code></pre>
  
  <p>What's the best practice to:</p>
  
  <ol>
  <li>add a new user { id: 4, name: "Jane" } with id (4) as key</li>
  <li>remove a user with id 2</li>
  <li>change the name of user #2 to "Peter"</li>
  </ol>
  
  <p>Without any immutable helpers. I'm using Coffeescript and Underscore (so _.extend is ok...).</p>
  
  <p>Thanks.</p>