I'm going to be writing a BDD driven app, initially just to run in a browser. I intend to write tests in typescript. I was very impressed with Fluent Assertions, as demonstrated in the Pluralsight course "Pragmatic Behavior-driven Design with .NET" by Rob Conery. He used it together with xUnit.net. I want to be able to run front end tests in a similar fashion. So far, I've only found one candidate in this vein, assertchain-jasmine (on GitHub). It's a much smaller library than FluentAssertions.