hd-utils/lib/utils/array/groupBy.d.ts

A handy utils for modern JS developers

import { GroupedObject } from '../types';
/**
 * @description function to categorizes an array of objects by a key or condition. It also supports optional object transformation before grouping.
 * @example
 *
groupBy(
  [
  { name: 'Alice', age: 25 },
  { name: 'Bob', age: 30 },
  { name: 'Charlie', age: 25 },
  { name: 'David', age: 30 },
],
  'age',
  (person) => ({ ...person, isNew: person.age < 30 })
) //
{
  25: [
    { name: 'Alice', age: 25, isNew: true },
    { name: 'Charlie', age: 25, isNew: true },
  ],
  30: [
    { name: 'Bob', age: 30, isNew: false },
    { name: 'David', age: 30, isNew: false },
  ],
};

 */
export default function groupBy<T>(array: T[], keyOrCondition: string | ((item: T) => string), transform?: (item: T, key: string) => T): GroupedObject<T>;