react-native-community-cli/docs/configuration.md

Configuration

React Native CLI has a configuration mechanism that allows changing its behavior and providing additional features.

Note: Configuring CLI used to be possible via rn-cli.config.js (that has been renamed to metro.config.js) and never documented rnpm entry on the package.json. We have provided migration guides where possible.

React Native CLI can be configured by creating a react-native.config.js at the root of the project. Depending on the type of a package, the set of valid properties is different.

Check the documentation for

• projects
• dependencies
• platforms
• plugins

to learn more about different types of configuration and features available.