title: setInterval function without arrow function
body: <p>I am learning about react components following the documentation <a href="https://facebook.github.io/react/docs/state-and-lifecycle.html" rel="noreferrer">https://facebook.github.io/react/docs/state-and-lifecycle.html</a></p>
  
  <p>Why do we need to use arrow function here:</p>
  
  <pre><code>this.timerID = setInterval(() =&gt; this.tick(), 1000);
  </code></pre>
  
  <p>Why can't I just say (obviously it doesn't work)</p>
  
  <pre><code>this.timerID = setInterval(this.tick(), 1000);
  </code></pre>