title: React-dnd what does $splice do
body: <p>I am reading <a href="https://github.com/gaearon/react-dnd/blob/master/examples/04%20Sortable/Simple/Container.js#L48" rel="noreferrer">an example of the React-dnd project</a>:</p>
  
  <pre><code>moveCard(dragIndex, hoverIndex) {
      const { cards } = this.state;
      const dragCard = cards[dragIndex];
  
      this.setState(update(this.state, {
        cards: {
          $splice: [
            [dragIndex, 1],
            [hoverIndex, 0, dragCard]
          ]
        }
      }));}
  </code></pre>
  
  <p>Is this $splice the same one explained <a href="https://facebook.github.io/react/docs/update.html" rel="noreferrer">on this page</a>? </p>
  
  <p>Could anybody explain what does this chunk of code do? The <code>$splice</code> function is very confusion to me.</p>