Memoization is a powerful technique used to optimize the performance of functions by caching their results. It is particularly useful when a function is called multiple times with the same set of input arguments. By storing the computed results in a cache, subsequent calls can be served directly from the cache without re-executing the function.

In JavaScript, we can implement a memoization pattern using a Proxy object. The Proxy object allows us to intercept and customize operations performed on an object, including function calls. By leveraging this feature, we can create a memoization proxy that transparently caches function results.

Let’s take a look at an example:

function memoize(fn) {
  const cache = new Map();

  return new Proxy(fn, {
    apply(target, thisArg, args) {
      const key = args.toString();

      if (cache.has(key)) {
        return cache.get(key);
      }

      const result = target.apply(thisArg, args);
      cache.set(key, result);

      return result;
    }
  });
}

In the code above, we define a memoize function that takes a function fn as an argument. Inside the memoize function, we create a cache using a Map to store the results.

We then create a Proxy object that intercepts function calls and checks if the result is already cached. If so, it returns the cached result, otherwise, it calls the original function and stores the result in the cache.

To use the memoize function, we can simply wrap any expensive function with it. Here’s an example:

function fibonacci(n) {
  if (n <= 1) {
    return n;
  }

  return fibonacci(n - 1) + fibonacci(n - 2);
}

const memoizedFibonacci = memoize(fibonacci);

console.log(memoizedFibonacci(10)); // 55
console.log(memoizedFibonacci(10)); // 55 (result served from cache)

In the code above, we define a Fibonacci function and then create a memoized version of it using the memoize function. We can see that the first call to memoizedFibonacci(10) computes and returns the result, while the second call retrieves the result from the cache, resulting in a significant performance improvement.

By leveraging the power of the Proxy object, we can easily implement a memoization pattern in JavaScript and optimize function calls with repetitive arguments.

#JavaScript #Memoization