title: Substitute bitwise operation in ESLint
body: <p>I'm trying to apply this code: <a href="https://stackoverflow.com/questions/21513646/how-to-get-x-y-z-coordinates-of-tile-by-click-on-leaflet-map">How to get X Y Z coordinates of tile by click on Leaflet map</a> - which contains bitwise operator "&lt;&lt;". In the environment that I'm running it on (NodeJS, ExpressJS, AngularJS), codes are checked by ESLint upon compiling it but I need the solution given on the link. I get this error on compilation .</p>
  
  <blockquote>
    <p>Unexpected use of '&lt;&lt;'  no-bitwise</p>
  </blockquote>
  
  <p>According to this link: <a href="http://eslint.org/docs/rules/no-bitwise" rel="noreferrer">http://eslint.org/docs/rules/no-bitwise</a> - ESLint disallows bitwise operators. Is there any way to bypass this rule or if not, provide an alternate calculation  that produces similar results to bitwise operation '&lt;&lt;'? </p>
  
  <p>I hope my question is clear, thanks.</p>