The clojure/clojurescript tooling for QuickCheck is quite powerful - as it has a wide range of generators which are able to generate smarter / more specific dat

The clojure/clojurescript tooling for QuickCheck is quite powerful - as it has a wide range of generators which are able to generate smarter / more specific data than simply matching on types. And since clojurescript can be compiled and exported to JavaScript, this makes it available to JavaScript projects. A few years ago I packaged this up as https://github.com/glenjamin/checkers https://github.com/glenjamin/checkers. I expect there are newer versions of the underlying library available now, but as I haven't been working in this ecosystem for a while, I haven't kept the package up to date.