Comment by motorest

> The original example was (paraphrasing) "rerunning 10-100 tests that take 1ms after each keystroke".

Yeah, OP's point is completely unrealistic and doesn't reflect real-world experience. This sort of test watchers is mundane in any project involving JavaScript, and not even those tests re-run at each keystroke. Watch mode triggers tests when they detect changes, and waits for test executions to finish to re-run tests.

This feature consists of running a small command line app that is designed to run a command whenever specific files within a project tree are touched. There is zero requirement to only watch for JavaScript files or only trigger npm build when a file changes.

To be very clear, this means that right now anyone at all, including you and me, can install a watcher, configure it to run make test/cutest/etc when any file in your project is touched, and call it a day. This is a 5 minute job.

By the way, nowadays even Microsoft's dotnet tool supports watch mode, which means there's out-of-the-box support to "rerunning 10-100 tests that take 1ms after each keystroke".