@streetscape.gl/monochrome/src/utils/memoize.js

A toolkit of React components for streetscape.gl

// Copyright (c) 2019 Uber Technologies, Inc.
//
// 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.
function isEqual(arr1, arr2) {
  const len = arr1.length;
  if (len !== arr2.length) {
    return false;
  }
  for (let i = 0; i < len; i++) {
    if (arr1[i] !== arr2[i]) {
      return false;
    }
  }
  return true;
}

/**
 * Speed up consecutive function calls by caching the result of calls with identical input
 * https://en.wikipedia.org/wiki/Memoization
 * @param {function} compute - the function to be memoized
 */
export default function memoize(compute) {
  let cachedArgs = [];
  let cachedResult;

  return function memoizedFunc() {
    if (!isEqual(arguments, cachedArgs)) {
      cachedResult = compute.apply(this, arguments);
      cachedArgs = Array.from(arguments);
    }
    return cachedResult;
  };
}