MemoizeMFU.js

// Memoize is a Proxy to the actual function
const memoize = (fn, mfu = 10) => new Proxy(fn,

  // Handler with traps
  {
    cache: new MFUMap(mfu),
    max: mfu,   // Our cache limit

    // Our "magic" property
    get(object, property, receiver) {
      if (property == "cache")
        return this.cache;

      return Reflect.get(object, property, receiver);
    },

    // Intercept call to the wrapped function
    apply(target, thisArg, args) {

      let result = this.cache.get(args.toString());
      
      if (result)
        return result;
      
      result = Reflect.apply(target, thisArg, args);
      this.cache.set(args.toString(), result);

      return result;
    }
  }
);