mirror of
https://gitlab.com/openstapps/openstapps.git
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46 lines
1.6 KiB
TypeScript
46 lines
1.6 KiB
TypeScript
/*
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* Copyright (C) 2022 StApps
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* This program is free software: you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the Free
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* Software Foundation, version 3.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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/**
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* Group an array by a function
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*/
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export function groupBy<T>(collection: T[], group: (item: T) => string | undefined): Record<string, T[]> {
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return collection.reduce((accumulator: Record<string, T[]>, item) => {
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const key = group(item) ?? '';
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accumulator[key] = accumulator[key] ?? [];
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accumulator[key]!.push(item);
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return accumulator;
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}, {});
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}
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/**
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* Group an array by a function (returns a Map, whose keys keep order info of items entry)
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*/
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export function groupByStable<T>(collection: T[], group: (item: T) => string | undefined): Map<string, T[]> {
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return collection.reduce((accumulator: Map<string, T[]>, item) => {
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const key = group(item) ?? '';
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accumulator.set(key, accumulator.get(key) ?? []);
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accumulator.get(key)?.push(item);
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return accumulator;
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}, new Map<string, T[]>());
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}
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/**
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*
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*/
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export function groupByProperty<T extends object>(collection: T[], property: keyof T): Record<string, T[]> {
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return groupBy(collection, item => item[property] as unknown as string);
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}
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