code: function expand(object, delimiter) {
      var expanded = {};
  
      delimiter = delimiter || '.';
  
      forEach(object, function (value, key) {
        var keys    = key.split(delimiter),
            current = expanded;
  
        while (keys.length) {
          key = keys.shift();
  
          if (!current.hasOwnProperty(key)) {
            if (keys.length === 0) {
              current[key] = value;
            } else {
              current[key] = {};
            }
          }
  
          current = current[key];
        }
      });
  
      return expanded;
    }
docs: /* Public: Rebuilds a flattened object into a deeply nested
  object. An optional delimiter can be provided.
  
  object    - Object to rebuild.
  delimiter - String to use as a delimiter (default: ".").
  
  Examples
  
  var obj = {'a.b': 'leaf 1', 'ac': 'leaf 2'}
  expand(obj);
  // => {a: {b: 'leaf 1', c: 'leaf 2'}}
  
  Returns expanded Object.