There are at least 4 reasons I can think of that you don't want to write JS without knowing how to use a transpiler, a search will probably find great lists and

There are at least 4 reasons I can think of that you don't want to write JS without knowing how to use a transpiler, a search will probably find great lists and explanations.. Once you are using one, it makes sense to use typescript and stay close to JS (good for staying close to definitive DOM/BOM guides and debugger results) or an entirely different language that transpiler to JS, for some preferred style. But (once transpiling) there's very few advantages to JS itself over using typescript even with the most occasional use of types for debugging a bad return or variable etc. The other route to take is to try to follow the cutting edge of webassembly, so you can continue to use a lot of python. Python is probably going to be first in it's class of languages for support at each step, but it's class is not as ideal for webassembly as non-gc strongly typed languages which are ironically less like Python than JS!