Problem Description

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.

Solution

/**
 * @param {Function} fn
 * @return {Function}
 */
function memoize(fn) {
    const cache = new Map();
    
    return function(...args) {
        // Create a unique key for the arguments
        // Note: For simple primitives, joining is often enough, 
        // but JSON.stringify handles arrays/objects better as keys 
        // (though slower and has edge cases with circular refs).
        // For this specific problem context where args are JSON serializable:
        const key = JSON.stringify(args);
        
        if (cache.has(key)) {
            return cache.get(key);
        }
        
        const result = fn(...args);
        cache.set(key, result);
        return result;
    }
}