preact-scoped-model/src/utils/comparer.ts

Scoped Model pattern for Preact

/**
 * @license
 * MIT License
 *
 * Copyright (c) 2021 Alexis Munsayac
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 *
 * @author Alexis Munsayac <alexis.munsayac@gmail.com>
 * @copyright Alexis Munsayac 2021
 */
export type Compare<T> = (a: T, b: T) => boolean;

export function defaultCompare<T>(a: T, b: T): boolean {
  return !Object.is(a, b);
}

type ArrayType<T> = T extends Array<infer U> ? U : T;

export type ListCompare<T extends any[]> = Compare<ArrayType<T>>;

export function compareList<T extends any[]>(
  a: T, b: T,
  compare: Compare<ArrayType<T>> = defaultCompare,
): boolean {
  if (a === b) {
    return false;
  }
  if (a.length !== b.length) {
    return true;
  }
  for (let i = 0; i < a.length; i += 1) {
    if (compare(a[i], b[i])) {
      return true;
    }
  }
  return false;
}