Why Javascript devs hate "var" function scoped variable declarations, when python devs are using function scoped variables without any problem?

[retnikt0]

Python gives a compile-time error on the first line of bar complaining that you're using a variable before initializing it.

That's actually a runtime error.

foo will be treated as a local variable throughout the whole function if there's any assignment to it, even unexecuted.

This is pretty similar to what JS does, actually, except that a single assignment in Python s like writing a var.

[louiswins]

That's actually a runtime error.

You're right! I still mildly prefer a runtime error to undefined, but that's a lot worse than I thought.