I know I sound a little ignorant, but could you elaborate a little on nullability. I mean is it the same as checking whether an assignment is null or not?
P.S. I haven't used either typescript or flow.
P.S. I haven't used either typescript or flow.
For example, suppose you're building a simple app to remind you to call your friends on their birthdays. Your fields are name (a string), birthday (a date), and phone number (a string). Since it doesn't make sense to put somebody in without a name and birthday, you say those aren't nullable. But say you want to be able to leave a phone number out, because it's easy enough to look up their phone number when you want to call. So phone would nullable.
Java, as an example, required everything variable to be typed, but all references could be null. This meant that far and away the most common error in Java logs was NullPointerException. It's great to see language features aimed at reducing that.
I have the feeling that even if you would just use "any" (with excluded null and undefined) everywhere 90% of JS problems would go away.