std/bytes/ends_with.ts

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.

/** Returns true if the suffix array appears at the end of the source array,
 * false otherwise.
 *
 * The complexity of this function is O(suffix.length).
 *
 * ```ts
 * import { endsWith } from "https://deno.land/std@$STD_VERSION/bytes/mod.ts";
 * const source = new Uint8Array([0, 1, 2, 1, 2, 1, 2, 3]);
 * const suffix = new Uint8Array([1, 2, 3]);
 * console.log(endsWith(source, suffix)); // true
 * ```
 */
export function endsWith(source: Uint8Array, suffix: Uint8Array): boolean {
  for (
    let srci = source.length - 1, sfxi = suffix.length - 1;
    sfxi >= 0;
    srci--, sfxi--
  ) {
    if (source[srci] !== suffix[sfxi]) return false;
  }
  return true;
}