Typescript. When working in a shop with a large contingent of .NET developers, having a language that somewhat resembles what they are used to is a great asset.
It’s really helped reduce some of that 3rd party lib / buildchain JS fatigue for me.
Even with `--noImplicitAny`, it's gotten pretty easy. Leave a scratch .d.ts file somewhere in your project and when you install a new library you can start with:
declare module 'libraryname'
declare module 'libraryname/**/*'
The number of npm packages with types directly included is growing at an impressive rate (even Facebook often bundles them for React libraries), so there's not even the need to seek out types in so many cases these days.
I believe the latest version of Visual Studio Code can automatically install the type dependencies from the IDE (e.g. a quick fix if the type definitions are missing).