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