Runs your app in development mode.
Open it in the Expo app on your phone to view it. It will reload if you save edits to your files, and you will see build errors and logs in the terminal.
Sometimes you may need to reset or clear the React Native packager's cache. To do so, you can pass the --reset-cache flag to the start script:
npm start -- --reset-cache
# or
yarn start -- --reset-cache
Runs the jest test runner on your tests.
Like npm start, but also attempts to open your app in the iOS Simulator if you're on a Mac and have it installed.