There is only one option in testcafe --stop-on-first-fail which stops the whole test run not only fixture or file. Is it possible to somehow separate or isolate the fixtures or files? My goal is to separate files in failure, so if there is a failure in the test, it will stop the whole file/fixture and the test run will continue to another file/fixture. I assume, this feature is not implemented yet and I will have to use javascript.
There is no such functionality in TestCafe right now, and I can't see any workaround for this scenario. I recommend you create a suggestion in the TestCafe github repository using this form.