title: React Spring and useTransition
body: <p>I am trying to use react-spring and I have a very simple animation for a component that should be moounted/unmounted on toggle.</p>
  
  <pre><code>const state = useContext(MyContext)
    const transitions = useTransition(state.nav, null, {
      from: { tranform: 'translate3d(-100%, 0, 0)' },
      enter: { transform: 'translate3d(0, 0, 0)' },
      leave: { tranform: 'translate3d(-100%, 0, 0)' },
    })
    return transitions.map((item, key, props) =&gt; (
      &lt;animated.div style={props} key={key}&gt;
        &lt;Navigation items={items} /&gt;
      &lt;/animated.div&gt;
    ))
  </code></pre>
  
  <p>However when I run this in the browser I get this error:</p>
  
  <pre><code>Uncaught TypeError: Failed to set an indexed property on 'CSSStyleDeclaration': Index property setter is not supported.
  </code></pre>
  
  <p>Apart from using Context I can't see nothing wrong, when I look at other tutorial. 
  Any help is appreciated thanks!</p>