Memoization

let memoize = fn => {
  let cache = {};
  return (...args) => {
    let stringifiedArgs = JSON.stringify(args);
    let result = cache[stringifiedArgs] = cache[stringifiedArgs] || fn(...args);
    return result;
  };
};

let pureAdd = (x,y) => { return x + y }; // pure function

let memoizedAdd = memoize(pureAdd); // memoized pure function

memoizedAdd(3,4) // 7
memoizedAdd(3,4) // 7

// efficient and consistent!
//By - Jonathan Schapiro
//Link: https://medium.com/front-end-hacking/today-i-learned-memoization-with-pure-functions-in-es6-33a4765518b5

• Line 1 - Our memoize function accepts a fn to be memoized.
• Line 2 - We initialize a new cache for the fn passed in utilizing the, ever so powerful, closure scope.
• Line 3 - We return the memoized fn which accepts some number of args.
• Line 4 - We stringify the arguments passed to our memoized fn to be used as a “key” to our cache.
• Line 5 - We then check the cache for the value associated with that key. If the value associated with that key exists in the cache we assign it to result otherwise we call fn with the arguments passed to the memoized function and assign its value to the cache.
• Line 6 - Finally, we return the result.