There is a longstanding issue with Metro not accepting symlinks and thus making it hard to use in monorepo setups or example projects. This script provides a solution.

This package generates a custom rn-cli.config.js file based on checking for symlinks inside the node_modules. It also takes care of making peer dependencies available to those symlinked modules.

# Install
yarn add -D metro-with-symlinks
# or
npm install -D metro-with-symlinks

In the most recent version of the metro bundler, you just need to have a rn-cli.config file in your root folder and it will automatically be read by the bundler. You can generate that file by running metro-with-symlinks without any argument in the terminal, which will generate the rn-cli.config file. You will have to regenerate this file, whenever you symlink another package or add a peerDependency to your link

In older versions, you have to tell the packager where to find the config file. To do so you can simply replace the standard react-native commands with this custom command. For example: replace the start script in your package.json with this:

"scripts": {
    "start": "metro-with-symlinks start",
}

# You will need to have run this or the start command above to generate rn-cli.config.js config.
yarn metro-with-symlinks

In Xcode you can assign an environment variable in the build phase Bundle React Native code and images. Add:

export BUNDLE_CONFIG=./rn-cli.config.js

In Android you just have to include bundleConfig: "./rn-cli.config.js" in the project.ext.react field of your android/app/build.gradle:

If there is a specific feature you are missing, please create an issue or ideally open a pull request.