Expo Phaser is a set of tools that allow you to use Phaser CE with Expo. Expo is a free and open source toolchain built around React NAtive to help you build native iOS and Android projects using JavaScript and React.
The Expo Phaser project maintains customized versions of Phaser CE to allow for more seamless use in the Expo environment and comes with example games and docs. If you're a React developer looking to break into apps, this is well worth checking out.