associateBy

function

function associateBy<T>(array: Iterable<T>, selector: (el: T) => string): Record<string, T>

Creates a record by associating each element of the input array with a key generated by the selector function.

If the selector produces the same key for multiple elements, the latest one will be used (overriding the ones before it).

array: Iterable<T>

The array to transform.

selector: (el: T) => string

The function to extract the key from each element.

Returns

A record with the keys produced by the selector and the elements as values.

import { associateBy } from "@ende/collections/associate-by";
import { assertEquals } from "@ende/assert";

const users = [
  { id: "a2e", userName: "Anna" },
  { id: "5f8", userName: "Arnold" },
  { id: "d2c", userName: "Kim" },
];

const usersById = associateBy(users, (user) => user.id);

assertEquals(usersById, {
  "a2e": { id: "a2e", userName: "Anna" },
  "5f8": { id: "5f8", userName: "Arnold" },
  "d2c": { id: "d2c", userName: "Kim" },
});