An Expo config plugin for including multiple custom URI schemes into Info.plist (CFBundleSchemes)

(iosCustomSchemes)app.json

// Usage example
{
  "expo": {
    "scheme": "primary scheme", // supported out of the box, but only single scheme
    ...
    "plugins": [
      ...
      ["./withIosCustomScheme", { customScheme: "extraScheme1" }],
      ["./withIosCustomScheme", { customScheme: "extraScheme2" }]
    ]
  }
}

withIosCustomScheme.js

// copied from https://github.com/expo/expo-cli/blob/master/packages/config-plugins/src/ios/Scheme.ts
function appendScheme(scheme, infoPlist) {
  if (!scheme) {
    return infoPlist;
  }

  const existingSchemes = infoPlist.CFBundleURLTypes;

  return {
    ...infoPlist,
    CFBundleURLTypes: [
      ...(existingSchemes ?? []),
      {
        CFBundleURLSchemes: [scheme],
      },
    ],
  };
}

const withIosCustomScheme = (config, { customScheme }) => {
  // Ensure the objects exist
  if (!config.ios) {
    config.ios = {};
  }
  if (!config.ios.infoPlist) {
    config.ios.infoPlist = {};
  }

  // Append the scheme
  config.ios.infoPlist = appendScheme(customScheme, config.ios.infoPlist);

  return config;
};

module.exports = withIosCustomScheme;