Memoization with Closures

Memoization caches the results of expensive function calls. Closures make this elegant — the cache lives in the closure's scope.

function memoize(fn) {
  const cache = {};
  return function(n) {
    if (cache[n] !== undefined) {
      return cache[n];
    }
    cache[n] = fn(n);
    return cache[n];
  };
}

const slowSquare = n => n * n;
const fastSquare = memoize(slowSquare);
console.log(fastSquare(5)); // 25 (computed)
console.log(fastSquare(5)); // 25 (from cache)

YOUR TASK

Create a memoized version of a function that doubles its input. Call it with 8 twice and print each result on a separate line.

Need a hint?

Use the memoize example above with n => n * 2 as your function.

Expected Output:

16
16