Array/Lodash.chunk

_.chunk(array, [size=1])

source / npm package / lodash

Creates an array of elements split into groups the length of size. If array cant be split evenly, the final chunk will be the remaining elements

創建一個二維數組，元素被分組成若干個塊(chunk)，塊也是數組，其的長度為指定 size 的值。如果數組不能被平均分塊，最後一個塊將包含所有剩下的元素。

Since

• 3.0.0

Arugments

• array (Array): The array to process.
• [size=1] (number): The length of each chunk

Returns

• (Array): Returns the new array of chunks.

Example

online

_.chunk([a, b, c, d], 2);// => [[a, b], [c, d]] _.chunk([a, b, c, d], 3);// => [[a, b, c], [d]]

Source

/** * Creates an array of elements split into groups the length of `size`. * If `array` cant 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=1] The length of each chunk * @param- {Object} [guard] Enables use as an iteratee for methods like `_.map`. * @returns {Array} Returns the new array of 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, guard) { if (guard ? isIterateeCall(array, size, guard) : size === undefined) { size = 1; } else { size = nativeMax(toInteger(size), 0); } var length = array == null ? 0 : array.length; 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;}

源碼里有第三個參數，將 array, size, guard 對應到 value, index, object，來檢測 value 是否以 index 的位置存在於 object 里，如果是的話，就將 size 設置為 1；這樣做的目的，我不太清楚，但是能保證每一個塊的長度一致，就像文檔注釋寫的那樣，啟用迭代為了作用於 _.map 類似的方法？

轉載請備註作者及來源

如對本文有任何異議，歡迎評論區留言討論