title: React Transition Group V2 skipping the entering/exiting status
body: <p>I’m trying to get my head around React Transition Group V2</p>
  
  <p>I built a demo using create-react-app and the example in the documentation but it skips the entering/exiting status’ and doesn’t trigger a Transition.</p>
  
  <p>So far I have….</p>
  
  <p>Tried Inline (like in the documentation) and also using the class name, but same result.
  added and removed browser specific css
  Fiddled around with all the props, with little luck (although the appear prop did trigger ‘entering’ and run the transition)</p>
  
  <p>Here’s a link to the documentation: <a href="https://reactcommunity.org/react-transition-group/" rel="nofollow noreferrer">https://reactcommunity.org/react-transition-group/</a></p>
  
  <p>And here’s what I have.  (I know V2 is pretty new so any help will be greatly appreciated.)</p>
  
  <pre><code>import React, { Component } from 'react';
  import Transition from 'react-transition-group/Transition'
  
  class App extends Component {
  
    state = { show: false }
  
    handleClick = e =&gt; {
      this.setState({show: !this.state.show})
    }
    render() {
  
      const duration = 300;
  
      const defaultStyle = {
        transition: `opacity ${duration}ms ease-in-out`,
        opacity: 0,
      }
  
      const transitionStyles = {
        entering: { opacity: 1 },
        entered:  { opacity: 1 },
      };
  
      const Fade = ({ in: inProp }) =&gt; (
        &lt;Transition in={inProp} timeout={duration}&gt;
          {(state) =&gt; (
            &lt;div style={{
              ...defaultStyle,
              ...transitionStyles[state]
            }}&gt;
              I'm A fade Transition!
            &lt;/div&gt;
          )}
        &lt;/Transition&gt;
      );
  
      return (
        &lt;div className="App"&gt;
            &lt;Fade in={this.state.show}/&gt;
            &lt;button onClick={this.handleClick}&gt;TOGGLE&lt;/button&gt;
        &lt;/div&gt;
      );
    }
  }
  
  export default App;
  </code></pre>