px_to_rem

Replace your font-size: in px with font-size: in rem units

  $ npm install px_to_rem 

Utility for converting font-size css styles using px units to rem

  var px_to_rem = require('px_to_rem');
  var css = "h1 { \n font-size: 12px;\n }";
  
  var output = px_to_rem.convert(css);
  
  console.log(output);

Also included is a command line tool that takes a css file as an argument (cwd = base folder of plugin)

  $ ./px_to_rem style.css