dna_to_rna.js

// exercism.io exercise
var toRna = function (dna) {
  'use strict';
  var rnaMap = {
    'G' : 'C',
    'C' : 'G',
    'T' : 'A',
    'A' : 'U'
  };
  var rna = dna.replace(/G|C|T|A/gi, function(match){
    return rnaMap[match];
  });
  return rna;
};