code: function (string, size, begin) {
              if (!ariaUtilsType.isString(string)) {
                  return null;
              } else if (!string) {
                  return [string];
              }
  
              if (ariaUtilsType.isArray(size)) {
                  return this._chunkArray(string, size, begin);
              } else {
                  return this._chunkNumber(string, size, begin);
              }
          }
docs: Split a string into an array of chunks. The length of the chunks is given by size that can be either
  <ul>
  <li> a number, all chunks will have the same size, except the last one if shorter than size</li>
  <li> an array of numbers, chunks will respectively have same length as the number in the array. If the string
  is longer than the sum of array numbers, the last chunk will contain the remaining part of the string.</li>
  </ul>
  @param {String} string String to splitted
  @param {Number|Array} size Length of chunks. If an array, the element at position 0 is the length of the
  first chunk.
  @param {Boolean} begin If true chunks are created from right to left. Default false
  @return {Array} List of chunks. Calling join('') on this array always returns the initial string.
  @example
  
  <pre>
  chunk('abcdefg', 3, true);
  ['abc', 'def', 'g']
  
  chunk('abcdefg', 3, false);
  ['a', 'bcd', 'efg']
  
  chunk('abcdefg', [1, 2], true);
  ['ab', 'c', 'defg']
  
  chunk('abcdefg', [1, 2], false);
  ['abcd', 'e', 'fg']
  </pre>