title: React Native does not format numbers with thousand separators (,) when using toLocaleString()
body: <p>React Native does not format large numbers with "," as thousand separators when using toLocaleString('en-us'). 
  The same problem is observed on both Android and iOS versions. </p>
  
  <p>I am working on a simple calculator app for Android and iOS. 
  I previously created a similar model for web (plain javaScript) and made it work. However, since I ported it to React Native, the resulting calculation will no longer have thousand separators. 
  My React Native demo can be found here: </p>
  
  <p><a href="https://snack.expo.io/@leourushi/calculator-tolocalestring" rel="nofollow noreferrer">https://snack.expo.io/@leourushi/calculator-tolocalestring</a></p>
  
  <p>An example of my calculation function: </p>
  
  <pre><code>text1: ( b/ ((c/100) + 1) ).toLocaleString('en-US')  
  </code></pre>
  
  <p>As you can see, I've added toLocaleString() method at the end of the calculation. 
  But when the result is returned, it will not have "," as thousand separator. </p>
  
  <p>Is toLocaleString() function not supported in React Native?</p>