> I can't fathom a world where JavaScript is less efficient than Haskell.

You can't fathom a world where a compiler can more easily produce efficient machine code from a statically typed language with very few semantic corners than from a dynamically typed language with lots of sharp corners plus reflection? I think you may need to meditate on the task of compilation a for a bit.

Unless you mean efficient for the programmer, in which case you are mistaking the up front effort of getting things to type check for additional effort. Usually it spares you the same number of iterations in debugging and testing, and the type checker is a lot faster than running unit tests. Plus the first time you make a major refactor to a program by making the change and then fixing everywhere the type checker complains, and that turns out to be it, it all works, it feels like you just mutated into a superhero.

Efficient use of time I think the parent poster was referring to.

You could have the project finished quickier in Javascript. Would you disagree? Does choosing haskell increase development time (ignoring major rewrites)?

I'd say it depends heavily on what you're writing. If it involves graphics, Javascript is going to be substantially less annoying, at least initially. However, the version you write in Haskell will be much more reliable, and much easier to progressively refactor and scale up, whereas in JS, the weird edge cases and lack of static guarantees will gradually pile up and make the project a chore to maintain.

For something non graphics related that you're building by yourself, if you already know Haskell, it's a no brainer, due to the high expressivity ceiling. Once a team is involved, the right choice (as always) basically just depends on what people already know.

> You could have the project finished quickier in Javascript. Would you disagree?

That very much depends on the project (I have a lot of experience with Javascript, Typescript and Haskell).

maybe you shouldn't be spouting answers when you should be asking questions then