It exists. It’s fine. People obviously like it.
Some don’t, I’m one of them. I don’t see the advantage is very big at all. I don’t think it’s worth the trouble.
But that’s me.
Sometimes I doubt most hacker news commentors have ever worked in big corpo environments where you have to regularly review large PR in some broken webapp like GitHub.
Generally, you save some keystrokes to let other people (or future you) figure it out when reading. It seems like bad practice altogether for non trivial projects.
Those keystrokes are not just saved on writing, they make the whole code more legible and easier to mentally parse. When reading I don't care if the variable is a specific type, you're mostly looking whats being done to it, knowing the type becomes important later and, again, the IDE solves that for you.
The word "String" "Integer" et al. + "var" is too much real estate for being explicit. Sometimes, I'm looking at the decompiled source from some library that doesn't have a source package available.
> Those keystrokes are not just saved on writing, they make the whole code more legible and easier to mentally parse.
This is incorrect. Repeating it doesn't make it true. For trivial code (<10 lines) probably seems fine at the time. Lots of bad practices start with laziness.
Changing practice because an author thinks a function is small enough when it was written, is a recipe for unclean code with no clear guidelines on what to use or expect. Maybe they rather put the onus on a future reader; this is also bad practice.