Yang Guo | 4fd355c | 2019-09-19 08:59:03 | [diff] [blame] | 1 | var baseSlice = require('./_baseSlice'), |
| 2 | isIterateeCall = require('./_isIterateeCall'), |
| 3 | toInteger = require('./toInteger'); |
| 4 | |
| 5 | /* Built-in method references for those with the same name as other `lodash` methods. */ |
| 6 | var nativeCeil = Math.ceil, |
| 7 | nativeMax = Math.max; |
| 8 | |
| 9 | /** |
| 10 | * Creates an array of elements split into groups the length of `size`. |
| 11 | * If `array` can't be split evenly, the final chunk will be the remaining |
| 12 | * elements. |
| 13 | * |
| 14 | * @static |
| 15 | * @memberOf _ |
| 16 | * @since 3.0.0 |
| 17 | * @category Array |
| 18 | * @param {Array} array The array to process. |
| 19 | * @param {number} [size=1] The length of each chunk |
| 20 | * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`. |
| 21 | * @returns {Array} Returns the new array of chunks. |
| 22 | * @example |
| 23 | * |
| 24 | * _.chunk(['a', 'b', 'c', 'd'], 2); |
| 25 | * // => [['a', 'b'], ['c', 'd']] |
| 26 | * |
| 27 | * _.chunk(['a', 'b', 'c', 'd'], 3); |
| 28 | * // => [['a', 'b', 'c'], ['d']] |
| 29 | */ |
| 30 | function chunk(array, size, guard) { |
| 31 | if ((guard ? isIterateeCall(array, size, guard) : size === undefined)) { |
| 32 | size = 1; |
| 33 | } else { |
| 34 | size = nativeMax(toInteger(size), 0); |
| 35 | } |
| 36 | var length = array == null ? 0 : array.length; |
| 37 | if (!length || size < 1) { |
| 38 | return []; |
| 39 | } |
| 40 | var index = 0, |
| 41 | resIndex = 0, |
| 42 | result = Array(nativeCeil(length / size)); |
| 43 | |
| 44 | while (index < length) { |
| 45 | result[resIndex++] = baseSlice(array, index, (index += size)); |
| 46 | } |
| 47 | return result; |
| 48 | } |
| 49 | |
| 50 | module.exports = chunk; |