title: Can't find variable: PropTypes
body: <p>I am trying some react native code. </p>
  
  <p>Added props for my component based on the instructions given in this <a href="https://codeburst.io/props-and-state-in-react-native-explained-in-simple-english-8ea73b1d224e" rel="noreferrer">blog</a>.</p>
  
  <p>End up in the error, Can't find variable: PropTypes
  Found the same question in <a href="https://github.com/facebook/react-native/issues/20852" rel="noreferrer">github</a> but it was closed without any answers</p>
  
  <p>Couldn't get any clues.</p>