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Discussion on: 5 ways to refactor if/else statements in JS functions

greenroommate profile image
Haris Secic • Edited

I highly doubt that using objects instead of switches and ifs has same performance. I'm not limiting it to this scenario but talking about generic overview why should one avoid switches and ifs in favour of objects or hash maps. Reason I'm asking is because I know for a fact that compilers (including JIT ones) and maybe some interpreters have really good optimizations which can even remove branching in some cases but I have no idea would such thing kick in for objects in JS. I know that c++ compiler since 2017 or so has really good optimizations that can turn generics, branching, hahsmaps into few instructions all together. There was a nice conf were, I forgot his name, wrote code on left side and on the right there was assembly outout. I also know JIT in Java will sometimes kick in an replace some of your code with shorter instructions than on first complie. Question is will such things be done by WebKit or others for JS.
Reagarding the safety again it's about generic thing not thi particular piece. It's much easier to have switch with default case and even shorter than objects and relying that || will not be forgotten

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rasmusvhansen profile image

I think we are both right here.
You are right that there probably is a difference in performance.
And I am right that in the real world it will make no difference*.
I learned to always prefer readability and then profile if something is slow. It is usually not what you think that is slowing you down.

*Except in that 0.001% weird edge case

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xtofl profile image

Fyi . The c++ tool mentioned would be