title: What is the difference between state and props in React?
body: <p>I was watching a Pluralsight course on React and the instructor stated that props should not be changed. I'm now reading <a href="https://github.com/uberVU/react-guide/blob/master/props-vs-state.md">an article (uberVU/react-guide)</a> on props vs. state and it says </p>
  
  <blockquote>
    <p>Both props and state changes trigger a render update.</p>
  </blockquote>
  
  <p>Later in the article it says:</p>
  
  <blockquote>
    <p>Props (short for properties) are a Component's configuration, its options if you may. They are received from above and immutable.</p>
  </blockquote>
  
  <ul>
  <li>So props can change but they should be immutable?</li>
  <li>When should you use props and when should you use state? </li>
  <li>If you have data that a React component needs, should it be passed through props or setup in the React component via <code>getInitialState</code>?</li>
  </ul>