title: What does the variable "window" represent in react native?
body: <p>I'm looking at some code for react native fetch blob <a href="https://github.com/joltup/react-native-fetch-blob" rel="noreferrer">https://github.com/joltup/react-native-fetch-blob</a> and I see in their example to call <code>window.Blob</code>, etc..</p>
  
  <p>Is Window a global variable like you would see in a browser web environment?  Or does it represent the current viewable screen in some way?  Is the below code example just replacing/overriding a global object?</p>
  
  <pre><code>const Blob = RNFetchBlob.polyfill.Blob;
  const fs = RNFetchBlob.fs;
  window.XMLHttpRequest = RNFetchBlob.polyfill.XMLHttpRequest;
  window.Blob = Blob;
  </code></pre>