I’m not sure I’d say pure JS is easier to contribute to. Having type information around your codebase makes it much easier to know what comes from where, even if you haven’t traced the source of the variable all the way to the start.

Like, you are theoretically correct, but practically the extra complexity of using Typescript over Javascript is running ‘npm install typescript’ after installing node. You certainly have less build tooling without tsc, but the benefit there is tiny.

There’s some mild reasons to go for pure JS, and a lot of absolutely gigantic reasons to go for Typescript (in my opinion).