2623. Memoize

Given a function fn, return a memoized version of that function.
A memoized function is a function that will never be called twice with the same inputs. Instead it will return a cached value.

/**
 * @param {Function} fn
 * @return {Function}
 */
function memoize(fn) {
    
    return function(...args) {
        
    }
}


/** 
 * let callCount = 0;
 * const memoizedFn = memoize(function (a, b) {
 *	 callCount += 1;
 *   return a + b;
 * })
 * memoizedFn(2, 3) // 5
 * memoizedFn(2, 3) // 5
 * console.log(callCount) // 1 
 */

Решение
Рассмотрим решение:

function memoize(fn) {
    const cache = {};

    return function(...args) {
        const key = String(args);

        if (key in cache) {
            return cache[key];
        }

        const result = fn(...args);
        cache[key] = result;
        return result;
    }
}