Basic knowledge of javascript to learn JavaScript Stack.
Feel free to clone, fork, or contribute.
[1] https://www.dicoding.com/academies/256
[2] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/filter
[3] https://code.tutsplus.com/id/tutorials/how-to-use-map-filter-reduce-in-javascript--cms-26209 (Map, Filter, Reduce Explanation in Bahasa)
[4] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/typeof (Check type of variable)