36 lines
1.1 KiB
JavaScript
36 lines
1.1 KiB
JavaScript
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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export class Dedupe {
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constructor(createKey) {
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this.createKey = createKey || this.defaultCreateKey;
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}
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defaultCreateKey(item) {
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return item;
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}
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/**
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* Dedupe any number of grouped elements favoring those from earlier groups.
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*
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* @param {Array} groups Contains an arbitrary number of arrays of elements.
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* @returns {Array} A matching array of each provided group deduped.
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*/
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group(...groups) {
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const globalKeys = new Set();
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const result = [];
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for (const values of groups) {
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const valueMap = new Map();
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for (const value of values) {
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const key = this.createKey(value);
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if (!globalKeys.has(key) && !valueMap.has(key)) {
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valueMap.set(key, value);
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}
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}
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result.push(valueMap);
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valueMap.forEach((value, key) => globalKeys.add(key));
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}
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return result.map(m => Array.from(m.values()));
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}
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}
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