Testing

There are many different types of testing, but for frontend, we are mainly interested in the following:

Static - static type checking combined with linters capture common errors, like typos or incorrect syntax
Unit tests - focus on critical behavior, business logic and the functionality of your app
Integration tests - are making sure everything works together correctly
End-to-end (e2e) tests - automated click-testing of critical paths (instead of relying on your users to do it for you). Or visual regression testing comparing the implementation of designs.

Benefits

Efficient use of developers’ time by not having them test the solution manually
After every code change, you don’t need to manually retest it (making it less expensive and less time-consuming, since devs will focus only on development)
Easier cooperation between BE and FE (reduces interactions between platforms after each change)
Application stability
Reduce the number of bugs by a massive number
Ensure that every functionality works exactly as it is supposed to

Huge waste of money/time that could be used towards feature development
No one can ensure a “bugless” solution and the proper behavior of all functionalities
The bigger the solution, the more fragile it becomes
Really hard or almost impossible to do refactoring