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std/collections/chunk.ts

Deno standard library
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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Splits the given array into chunks of the given size and returns them * * Example: * * ```ts * import { chunk } from "https://deno.land/std@$STD_VERSION/collections/mod.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/testing/asserts.ts"; * * const words = [ 'lorem', 'ipsum', 'dolor', 'sit', 'amet', 'consetetur', 'sadipscing' ] * const chunks = chunk(words, 3) * * assertEquals(chunks, [ * [ 'lorem', 'ipsum', 'dolor' ], * [ 'sit', 'amet', 'consetetur' ], * [ 'sadipscing' ], * ]) * ``` */export function chunk<T>(array: readonly T[], size: number): T[][] { if (size <= 0 || !Number.isInteger(size)) { throw new Error( `Expected size to be an integer greater than 0 but found ${size}`, ); }
if (array.length === 0) { return []; }
const ret = Array.from<T[]>({ length: Math.ceil(array.length / size) }); let readIndex = 0; let writeIndex = 0;
while (readIndex < array.length) { ret[writeIndex] = array.slice(readIndex, readIndex + size);
writeIndex += 1; readIndex += size; }
return ret;}