memoize.js

// cache any function call, use the args as a key
const memoize = (fn) => {
  let cache = {};
  return (...args) => {
    if (cache[args]) {
      return cache[args];
    } else {
      let result = fn.apply(this, args);
      cache[args] = result;
      return result;
    }
  }
}

// const fastFn = memoize(slowFn);