lodash/chunk.js

define(['./_baseSlice', './toInteger'], function(baseSlice, toInteger) {

  /* Built-in method references for those with the same name as other `lodash` methods. */
  var nativeCeil = Math.ceil,
      nativeMax = Math.max;

  /**
   * Creates an array of elements split into groups the length of `size`.
   * If `array` can't be split evenly, the final chunk will be the remaining
   * elements.
   *
   * @static
   * @memberOf _
   * @since 3.0.0
   * @category Array
   * @param {Array} array The array to process.
   * @param {number} [size=0] The length of each chunk.
   * @returns {Array} Returns the new array containing chunks.
   * @example
   *
   * _.chunk(['a', 'b', 'c', 'd'], 2);
   * // => [['a', 'b'], ['c', 'd']]
   *
   * _.chunk(['a', 'b', 'c', 'd'], 3);
   * // => [['a', 'b', 'c'], ['d']]
   */
  function chunk(array, size) {
    size = nativeMax(toInteger(size), 0);

    var length = array ? array.length : 0;
    if (!length || size < 1) {
      return [];
    }
    var index = 0,
        resIndex = 0,
        result = Array(nativeCeil(length / size));

    while (index < length) {
      result[resIndex++] = baseSlice(array, index, (index += size));
    }
    return result;
  }

  return chunk;
});