memoization.js

memoization.js

const memoize = function(fn) {
  const cache = {};
  return function(...args) {
    const key = args.join();
    if (cache[key]) {
      console.log('from cache!');
      return cache[key];
    }
    return cache[key] = fn.apply(this, args);
  };
}

const foo = function(...args) {
  return args.reduce((res, el) => res + el, 0);
}

const fn = memoize(foo);

console.log(fn(1, 2));    // 3
console.log(fn(1, 2, 3)); // 6
console.log(fn(1, 2));    // 3 (from cache!)

// https://jsfiddle.net/b9dxfj2u/