title: How to read initial properties in React Native
body: <p>I am passing initial properties onto my React Native application. </p>
  
  <pre><code>NSDictionary *dictionary = @{@"testID": @"123"};
  </code></pre>
  
  <p>This is received on the React Native side, and it displays </p>
  
  <pre><code>{"rootTag":1,"initialProps":{"testID":"123"}}.
  </code></pre>
  
  <p>However, I am reading the data on React Native side as - </p>
  
  <pre><code>componentWillMount() {
    var token = this.props.testID;
    console.log("testID is " + token);
  }
  </code></pre>
  
  <p><strong>It gives error JSON value NSNull cannot be converted into NSString.</strong></p>
  
  <p><strong>testID is undefined</strong></p>