How to fix the message "IntelliSense failed to determine the exact completion list for this expression" in JavaScript?

Question

I would like to use Visual Studio to encode JS, but I'm not sure how to fix IS in order to use variable types correctly.

I get this message, although I have added all the necessary links. $gameMessagedeclared in the file rpg_managers.js.

I assume that this is due to the fact that after the declaration there nullassigned to a variable ( see here ). How to fix this without interfering with the file rpg_managers.js? Unfortunately, this is not as simple as C #, since there are no hardcoded types in JS.

Can I fix this easily, or do I need to use a different IDE for js? Because I think I saw someone using some other editor, and this problem did not arise.