Created
February 1, 2019 10:32
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Lodash's missing swap util to replace an element from a collection
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| import { map, iteratee } from 'lodash'; | |
| /** | |
| * Replaces elements from collection that matches predicate with replacement. | |
| * | |
| * @param {Array} collection The collection to replace in | |
| * @param {*} predicate The condition to determine which elements of collection | |
| * should be replaced | |
| * @param {*} replacement The value to use as a replacement of elements of | |
| * collection that matches the predicate | |
| */ | |
| export const swap = (collection, predicate, replacement) => { | |
| const condition = iteratee(predicate); | |
| return map(collection, (element) => { | |
| if (condition(element)) { | |
| return replacement; | |
| } | |
| return element; | |
| }); | |
| }; |
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| describe('#swap()', () => { | |
| it('replaces element from collection that matches predicate', () => { | |
| const collection = [ | |
| { id: 1, value: 'one' }, | |
| { id: 2, value: 'two' }, | |
| { id: 3, value: 'three' }, | |
| ]; | |
| const predicate = { id: 2 }; | |
| const replacement = { id: 4, value: 'four' }; | |
| const expected = [ | |
| { id: 1, value: 'one' }, | |
| { id: 4, value: 'four' }, | |
| { id: 3, value: 'three' }, | |
| ]; | |
| expect(swap(collection, predicate, replacement)).toEqual(expected); | |
| }); | |
| }); |
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