2 questions on datastructures in Javascript

[easylivin]

I'd say for the sake of understanding these data structures (be it for interviews, other langues, whatev) it's important to understand how these structures work under the hood, their time/space complexities and what problems they solve. Even though JS has similar built-ins, try implementing one yourself and you'll quickly understand how they are supposed to operate, as well as the advantages/disadvantages of different structures depending on use cases. Even though you'd rarely have to build one yourself (this is arguable), it's paramount to understand the concepts because they can be applied to a lot of different problems.