React Native Threads Async Performance Promise Congestion React Native Interview 9 4

Summary

set timeout with zero milliseconds doesn't run immediately. And a login, then profile, then posts flow can't run in parallel. These questions test more than React Native syntax — they test production debugging, performance, architecture, scalability ... Your JavaScript never touches the screen directly. So how does a Three API calls one after another take three times as long. Run them together and you only wait So, I was trying to return the response data I was getting from an Axios call wrapped in a AsyncStorage call. Reason being, I ... Close the app, reopen it, and the user is still logged in, still in dark mode. Something saved that data on the device. Takeaway: ... Every unit test passes, and the login flow is still broken. Only a test that drives the real app, a real user, catches that. Crashes you can't reproduce, dark mode that must switch instantly, and a search box that hammers your API. Everyday production ...