Files
openstapps/src/app/_helpers/collections/group-by.ts
2022-05-03 11:06:06 +00:00

40 lines
1.2 KiB
TypeScript

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