@rws-air/utils/dist/Stack/GroupBy.d.ts

Utilities for rws-air libraries and applications

import { Stack } from './Stack';
/**
 * Group the elements of the input array to a Stack using the keyExtractor and valueExtractor the
 * to obtain the key and value for each element.
 * @param input The array of data to group into a Stack
 * @param keyExtractor A function that describes where to find the key to use for the Stack
 * @param valueExtractor A function that describes where to find the value to use for the Stack
 * @see Stack
 * @example
 * ```ts
 *  type HumanGenders = 'male' | 'female' | 'unknown';
 *
 *  interface Human {
 *    id: number;
 *    name: string;
 *    age: number;
 *    gender: HumanGenders;
 *  }
 *
 *  const humans: Human[] = [
 *    { id: 1, name: 'John Connor', age: 9001, gender: 'male' },
 *    { id: 2, name: 'Sarah Connor', age: 300, gender: 'female' },
 *    { id: 3, name: 'Luke Skywalker', age: 30, gender: 'male' }
 *  ];
 *
 *  const humansGroupedByGender = groupBy<Human, HumanGenders, Human>(
 *    humans,
 *    (h) => h.gender,
 *    (h) => h
 *  ); // Stack<HumanGenders, Human[]>
 *
 *  //  Stack(2) [Map] {
 *  //   'male' => [
 *  //     { id: 1, name: 'John Connor', age: 9001, gender: 'male' },
 *  //     { id: 3, name: 'Luke Skywalker', age: 30, gender: 'male' }
 *  //   ],
 *  //   'female' => [ { id: 2, name: 'Sarah Connor', age: 300, gender: 'female' } ]
 *  // }
 * ```
 * @returns A `Stack<Key, Value[]>` of the grouped values
 */
export declare function groupBy<I, K, V>(input: Array<I>, keyExtractor: (_: I) => K, valueExtractor: (_: I) => V): Stack<K, V[]>;
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