Lately I’ve noticed that when I do make a mistake in my code, “building javascript bundle” freezes even when I fix the syntax error. I have no choice but to quit simulator, restart cache, re-open simulator to get moving again.
I think this can happen if you make a typo around an import. I believe we restart watchman by default in this case in order to mitigate the issue. Is it happening to you for all errors? What OS/exp version/node version/RN version are you using?