I'm about to embark on building a client-side javascript tool intended to help with enwiki's [[WP:DYK]] process. JS is not my strength (and what I do know about tooling is quite outdated) so I'm looking for advice on what's in common use in the WMF environment these days. If I'm going to learn some new tools, I figure I might as well learn what folks here are using. If only because it'll make it easier for me to mooch on other people for help :-)
As far as testing goes, I used to use JUnit. I gather that's pretty old-hat by now. What are you-all using?
And for app frameworks. Angular? React? I hear Vie might be the new hotness? I'm leaning more towards "easy to learn" vs "most powerful".