utils.js

(function(global) {

  function capitalize(string) {
    return string.charAt(0).toUpperCase() + string.slice(1);
  }

  function pad(str, length) {
    while (str.length < length) {
      str = '0' + str;
    }
    return str;
  }

  var getRandomInt = fabric.util.getRandomInt;
  function getRandomColor() {
    return (
      pad(getRandomInt(0, 255).toString(16), 2) +
      pad(getRandomInt(0, 255).toString(16), 2) +
      pad(getRandomInt(0, 255).toString(16), 2)
    );
  }

  function getRandomNum(min, max) {
    return Math.random() * (max - min) + min;
  }

  function getRandomLeftTop() {
    var offset = 50;
    return {
      left: fabric.util.getRandomInt(0 + offset, 700 - offset),
      top: fabric.util.getRandomInt(0 + offset, 500 - offset)
    };
  }

  var supportsInputOfType = function(type) {
    return function() {
      var el = document.createElement('input');
      try {
        el.type = type;
      }
      catch(err) { }
      return el.type === type;
    };
  };

  var supportsSlider = supportsInputOfType('range'),
      supportsColorpicker = supportsInputOfType('color');

  global.getRandomNum = getRandomNum;
  global.getRandomInt = getRandomInt;
  global.getRandomColor = getRandomColor;
  global.getRandomLeftTop = getRandomLeftTop;
  global.supportsSlider = supportsSlider;
  global.supportsColorpicker = supportsColorpicker;
  global.capitalize = capitalize;

})(this);