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std/collections/unzip.ts

Deno standard library
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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Builds two separate arrays from the given array of 2-tuples, with the first returned array holding all first * tuple elements and the second one holding all the second elements * * Example: * * ```ts * import { unzip } from "https://deno.land/std@$STD_VERSION/collections/mod.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/testing/asserts.ts"; * * const parents = [ * [ 'Maria', 'Jeff' ], * [ 'Anna', 'Kim' ], * [ 'John', 'Leroy' ], * ] as [string, string][]; * * const [ moms, dads ] = unzip(parents); * * assertEquals(moms, [ 'Maria', 'Anna', 'John' ]); * assertEquals(dads, [ 'Jeff', 'Kim', 'Leroy' ]); * ``` */export function unzip<T, U>(pairs: readonly [T, U][]): [T[], U[]] { const { length } = pairs; const ret: [T[], U[]] = [ Array.from({ length }), Array.from({ length }), ];
pairs.forEach(([first, second], index) => { ret[0][index] = first; ret[1][index] = second; });
return ret;}