Format Utility

format.js

var format = function () {
  var args = Array.apply(null, arguments);
  var initial = args.shift();

  var replacer = function (text, replacement) {
    return text.replace('%s', replacement);
  }
  return args.reduce(replacer, initial);
}

// usage:
// var myName = 'david';
// format('hello %s', myName);
// prints hello david