title: React Native access this.state.key from another state key
body: <p>I have an issue with state key that I want to set it only if other states have the value of X.</p>
  
  <pre><code>this.state = {
    //display items
    setLanguage:'eng',
    language:this.state.setLanguage=='eng'?Language.eng:Language.heb,
  </code></pre>
  
  <p>If I set the language to this.state I get the all state <strong>keys</strong> and <strong>values</strong>, but if I try to set it to </p>
  
  <pre><code>language:this.state.setLanguage
  </code></pre>
  
  <p>I get the error:</p>
  
  <blockquote>
    <p>TypeError: undefined is not an object (evaluating
    '_this.state.setLanguage')</p>
  </blockquote>