[Eridrus]

Most web front-end code exists a single page at a time, and encompasses a pretty narrow range of functionality, so you can get away with fewer abstractions/patterns/etc since your whole program is pretty simple.

I think Redux (often used with React/React Native) looks a bit like ECS, at least to the extent that they both use an event/action-oriented approach.

But web front ends are just far simpler than games, and so the main priority is how to make them look like the designers want and how to crank them out quickly, rather than how to manage a lot of complexity.