During these days I see many articles about this "stuff" declarations war.
I think we can summarise everything in a few lines:
var: why? if you can avoid it, do it;
constusage if possible of course (together with an immutable approach when updating objects)! But don't be scared using
let, especially if the scope of your variables is small, for example inside a function.
Immutable things are cool when they really help, but just keep in mind that (imho) the most important thing is to have maintainable and readable software because we are a community of devs, teammates.
Happy new year! 🎉