React Native Socket.io User

user.js

// Client side
determineUser() {
  AsyncStorage.getItem('userId')
    .then((userId) => {
      if (userId) {
        this.socket.emit('i-dont-need-an-id');
      } else {
        this.socket.emit('i-need-id');
        this.socket.on('here-is-your-id', (id) => {
          AsyncStorage.setItem('userId', id);
          // Force a rerender in the React component
          this.setState({ id });
        });
      }
  });
}

// Server side
socket.on('i-need-id', () => {
  // Create a document in the db and grab that id.
  var user = db.collection('users').insert({});
  socket.emit('here-is-your-id', user._id);
});