const factorial = () => {
  const cached = {}
  return function(num) {
    console.time('NOT')
    console.time('CHACHED')
    console.log(cached)
    if (cached[num]) {
      console.timeEnd('CHACHED')
      return cached[num]
    }
    let result = 1
    for (let i = 1; i <= num; i++) {
      result = result * i
    }
    console.timeEnd('NOT')
    cached[num] = result
    return result
  }
}

const memFact = factorial()
console.log(memFact(50))
console.log(memFact(50))

const memoize = fn => {
  const cache = {}
  return (...args) => {
    let result
    console.time('NOT')
    console.time('CHACHED')
    if (cache[args[0]]) {
      console.timeEnd('CHACHED')
      return cache[args[0]]
    }
    result = fn(...args)
    console.timeEnd('NOT')
    cache[args[0]] = result
    return result
  }
}

const add = n => n + 10
console.log('Simple call', add(3))

const memoizedAdd = memoize(add)
console.log(memoizedAdd(3))
console.log(memoizedAdd(3))
console.log(memoizedAdd(4))
console.log(memoizedAdd(4))