Implementing Prettier would be good to keep all the JS consistent, similar to using Black on the python code: https://github.com/prettier/prettier
@ivanfon wrote some suggestions as well:
It’s worth noting that Node & NPM will likely be required anyways, as most JS-related tools are themselves written in JS/Node (eslint, prettier, babel, jsmin, etc). I don’t think this would be a huge issue though.
I think Babel would be a worthwhile addition (or at least using ES6). Most of the JS world has moved to ES6 already, and ES6 could probably be used on Tildes with no issues for the very large majority of users (modern browsers have had support for it for quite a while), but it’s still kind of a convention to transpile down to ES5 to ensure proper support on any browser.
Like I said, modern browsers support ES6 very well, so I don’t entirely think Babel is required, that just depends on how well Tildes wants to support users using outdated software. I know Tildes is fairly functional without scripts entirely, so I don’t think it would be the end of the world if the (very?) occasional user is using an older browser without ES6. Babel could also be used for some time, then removed at some point when deemed no longer necessary.
The output code shouldn’t have it’s size massively increased or be especially unreadable.
Considering how simple the client-side code is, this probably isn’t a big problem, but I think that a lot of people contributing will be used to ES6 (especially as time goes on), so it might be good to decide if ES6 should be allowed (whether plain or transpiled) sooner rather than later.