JavaScript: Memoization

Hey Guyz! I wanted to write a quick little blog about the memoization topic in JavaScript. At the start of my learning, the concept was so confusing to me(as was may other things lol), so I am writing this blog for you as well as for me solely for the purpose referring back to it in the future. Cool, lets get into it!

What is Memoization?

Memoization is cache return value of a function based on specific parameters. "When we input the same value into our memoized function, it returns the value stored in the cache instead of running the function again, thus boosting performance. No longer does your program have to recalculate every number to get a result."(Medium, codesmith Jan 17, 2018)

Memoization is essentially creating an object, checking for values matching the parameters, then storing new key-values that aren't available. Breaking down complex problems into tinier problems then storing it in a table(array, hash, and map)

function memoizeMultBy2() {
  const cache = {}
  return function (num) {
    if (num in cache) {
      return cache(num)
    } else {
      cache[num] = num * 2
      console.log("Loading....")
      return cache[num]
    }
  }
}

const memoize = memoizeMultBy2()
console.log(memoize(2))

I followed this algorithm by watching an explanation by youtuber Adam Coder. Summarizing the algorithm, we created a cache object, within the function we are also returning an function, we initialized and declared the variable memoize and invoked it so we are able to pass in a parameter. The first time we run this algorithm, we will get "Loading...." then the answer 4, when this algorithm is run again, the num parameter has already been cached so it displays the num without running through the algorithm again saving run time.

I hope this made sense and helped you, please let me know if there is anything you think I should clarify. Keep Smiling and enjoy life!