I personally don’t think that’s the issue with the typing system. With vanilla js if I’m looking at a function that has say four parameters that are not trivial objects like strings but are actually complex (think dependency injection) it’s very difficult for me to know what these objects are other than reading through the code of the function.

Actually, even if the parameters are simple, I’m not sure of that until I look into the function and see what it’s doing. This is a huge pain in the ass most the time, because I just wanna look at the function name its parameters and move on. However, that being said, most of this can be remedied with jsdocs and a good linter/lsp.