53 lines
1.3 KiB
JavaScript
53 lines
1.3 KiB
JavaScript
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/**
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* Copyright (c) 2015-present, Facebook, Inc.
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* All rights reserved.
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*
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* This source code is licensed under the BSD-style license found in the
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* LICENSE file in the root directory of this source tree. An additional grant
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* of patent rights can be found in the PATENTS file in the same directory.
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*
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* @providesModule groupByEveryN
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* @flow
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*/
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/**
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* Useful method to split an array into groups of the same number of elements.
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* You can use it to generate grids, rows, pages...
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*
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* If the input length is not a multiple of the count, it'll fill the last
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* array with null so you can display a placeholder.
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*
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* Example:
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* groupByEveryN([1, 2, 3, 4, 5], 3)
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* => [[1, 2, 3], [4, 5, null]]
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*
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* groupByEveryN([1, 2, 3], 2).map(elems => {
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* return <Row>{elems.map(elem => <Elem>{elem}</Elem>)}</Row>;
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* })
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*/
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'use strict';
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function groupByEveryN<T>(array: Array<T>, n: number): Array<Array<?T>> {
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var result = [];
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var temp = [];
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for (var i = 0; i < array.length; ++i) {
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if (i > 0 && i % n === 0) {
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result.push(temp);
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temp = [];
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}
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temp.push(array[i]);
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}
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if (temp.length > 0) {
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while (temp.length !== n) {
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temp.push(null);
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}
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result.push(temp);
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}
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return result;
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}
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module.exports = groupByEveryN;
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