Javascript String Interpolation

gistfile1.js

  function interpolate(source, dictionary) {
    return source.replace(/#{([^{}]*)}/g, function (a, b) {
      var r = dictionary[b];
      return typeof r === 'string' || typeof r === 'number' ? r : a;
    });
  }
// interpolate("#{first} #{last}", { first: "Shane", last: "Riley" });