react-native-firebase/lib/modules/auth/providers/FacebookAuthProvider.js

/**
 * @flow
 * FacebookAuthProvider representation wrapper
 */
const providerId = 'facebook.com';

export default class FacebookAuthProvider {
  constructor() {
    throw new Error('`new FacebookAuthProvider()` is not supported on the native Firebase SDKs.');
  }

  static get PROVIDER_ID(): string {
    return providerId;
  }

  static credential(token: string): AuthCredential {
    return {
      token,
      secret: '',
      providerId,
    };
  }
}