mirror of
https://github.com/denoland/std.git
synced 2024-11-22 04:59:05 +00:00
87 lines
2.4 KiB
TypeScript
87 lines
2.4 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
|
|
// This module is browser compatible.
|
|
|
|
/** Options for {@linkcode slidingWindows}. */
|
|
export interface SlidingWindowsOptions {
|
|
/**
|
|
* 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;
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* @typeParam T The type of the array elements.
|
|
*
|
|
* @param array The array to generate sliding windows from.
|
|
* @param size The size of the sliding windows.
|
|
* @param options The options for generating sliding windows.
|
|
*
|
|
* @returns A new array containing all sliding windows of the given size.
|
|
*
|
|
* @example Usage
|
|
* ```ts
|
|
* import { slidingWindows } from "@std/collections/sliding-windows";
|
|
* import { assertEquals } from "@std/assert";
|
|
* 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,
|
|
options: SlidingWindowsOptions = {},
|
|
): T[][] {
|
|
const { step = 1, partial = false } = options;
|
|
|
|
if (
|
|
!Number.isInteger(size) || !Number.isInteger(step) || size <= 0 || step <= 0
|
|
) {
|
|
throw new RangeError("Both size and step must be positive integer.");
|
|
}
|
|
|
|
return Array.from(
|
|
{ length: Math.floor((array.length - (partial ? 1 : size)) / step + 1) },
|
|
(_, i) => array.slice(i * step, i * step + size),
|
|
);
|
|
}
|