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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Transforms the given array into a Record, extracting the key of each element * using the given selector. If the selector produces the same key for multiple * elements, the latest one will be used (overriding the ones before it). * * @example * ```ts * import { associateBy } from "https://deno.land/std@$STD_VERSION/collections/associate_by.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/testing/asserts.ts"; * * const users = [ * { id: "a2e", userName: "Anna" }, * { id: "5f8", userName: "Arnold" }, * { id: "d2c", userName: "Kim" }, * ]; * const usersById = associateBy(users, (it) => it.id); * * assertEquals(usersById, { * "a2e": { id: "a2e", userName: "Anna" }, * "5f8": { id: "5f8", userName: "Arnold" }, * "d2c": { id: "d2c", userName: "Kim" }, * }); * ``` */export function associateBy<T>( array: readonly T[], selector: (el: T) => string,): Record<string, T> { const ret: Record<string, T> = {};
for (const element of array) { const selectedValue = selector(element);
ret[selectedValue] = element; }
return ret;}