# ./components/Messages.js

...

  static navigationOptions = ({ navigation }) => ({
    title: navigation.state.params.roomName,

...

  constructor(props) {
    super(props);
    var FirebaseDB = firebaseApp.database();
    var FirebaseUser = firebaseApp.auth().currentUser;
    var roomKey = this.props.navigation.state.params.roomKey;
    this.messagesRef = FirebaseDB.ref(`messages/${roomKey}`);
    this.state = {
      user: FirebaseUser,
      messages: []
    }
  }

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