128: Memoization

 Today's JS challenge is about Memoization. They ask you to write a function that accepts another function, and it caches the result of the function calls. If the result has already been computed, we return the cached value without having to run the function again. If no value is stored, we compute the value, store it, and return it. I accomplished this by declaring an object in my outer function to serve as a the cache. We then return a function that accepts an arbitrary number of arguments. I chose to use the JSON.stringify() method to turn the arguments into a usable object key. We check if the key is in our cache, and if so, return its value. Otherwise we compute its value based on the function and arguments, add it to our cache, and return.