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51 lines
1.3 KiB
TypeScript
51 lines
1.3 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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/**
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* Builds two separate arrays from the given array of 2-tuples, with the first
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* returned array holding all first tuple elements and the second one holding
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* all the second elements.
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*
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* @typeParam T The type of the first tuple elements.
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* @typeParam U The type of the second tuple elements.
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*
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* @param pairs The array of 2-tuples to unzip.
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*
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* @returns A tuple containing two arrays, the first one holding all first tuple
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* elements and the second one holding all second elements.
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*
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* @example Basic usage
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* ```ts
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* import { unzip } from "@std/collections/unzip";
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* import { assertEquals } from "@std/assert";
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*
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* const parents = [
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* ["Maria", "Jeff"],
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* ["Anna", "Kim"],
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* ["John", "Leroy"],
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* ] as [string, string][];
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*
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* const [moms, dads] = unzip(parents);
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*
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* assertEquals(moms, ["Maria", "Anna", "John"]);
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* assertEquals(dads, ["Jeff", "Kim", "Leroy"]);
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* ```
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*/
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export function unzip<T, U>(pairs: readonly [T, U][]): [T[], U[]] {
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const { length } = pairs;
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const result: [T[], U[]] = [
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new Array<T>(length),
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new Array<U>(length),
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];
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for (let i = 0; i < length; ++i) {
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const pair = pairs[i] as [T, U];
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result[0][i] = pair[0];
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result[1][i] = pair[1];
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}
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return result;
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}
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