- advance web applications (electron, NodeJS)
- ETL on the go (i.e. fetch, JSON, DOM, SVG)
- data visualization (i.e. d3, three.js, etc.)
- dependency management (i.e. NPM, CDN, ESM like in Deno)
- learning resources in general (extremely abundant and comprehensive on various sources)
It is hard not to learn JavaScript, it is almost everywhere. Also having to learn the 2nd or the 3rd programming language should also fill-in those gaps, even those huge gaps.