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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.// This module is browser compatible.
/** * Generates sliding views of the given array of the given size and returns a new * array containing all of them. * * If step is set, each window will start that many elements after the last * window's start. (Default: 1) * * If partial is set, windows will be generated for the last elements of the * collection, resulting in some undefined values if size is greater than 1. * (Default: false) * * Example: * * ```ts * import { slidingWindows } from "https://deno.land/std@$STD_VERSION/collections/mod.ts"; * import { assertEquals } from "https://deno.land/std@$STD_VERSION/testing/asserts.ts"; * const numbers = [1, 2, 3, 4, 5]; * * const windows = slidingWindows(numbers, 3); * assertEquals(windows, [ * [1, 2, 3], * [2, 3, 4], * [3, 4, 5], * ]); * * const windowsWithStep = slidingWindows(numbers, 3, { step: 2 }); * assertEquals(windowsWithStep, [ * [1, 2, 3], * [3, 4, 5], * ]); * * const windowsWithPartial = slidingWindows(numbers, 3, { partial: true }); * assertEquals(windowsWithPartial, [ * [1, 2, 3], * [2, 3, 4], * [3, 4, 5], * [4, 5], * [5], * ]); * ``` */export function slidingWindows<T>( array: readonly T[], size: number, { step = 1, partial = false }: { /** * If step is set, each window will start that many elements after the last * window's start. (Default: 1) */ step?: number; /** * If partial is set, windows will be generated for the last elements of the * collection, resulting in some undefined values if size is greater than 1. * (Default: false) */ partial?: boolean; } = {},): T[][] { if ( !Number.isInteger(size) || !Number.isInteger(step) || size <= 0 || step <= 0 ) { throw new RangeError("Both size and step must be positive integer."); }
/** length of the return array */ const length = Math.floor((array.length - (partial ? 1 : size)) / step + 1);
const result = []; for (let i = 0; i < length; i++) { result.push(array.slice(i * step, i * step + size)); } return result;}