Luego de hacer pull a los files de logout y anadiendo el file RoomScreen.js

screens/main/RoomScreen.js

@@ -0,0 +1,56 @@
+import React, { useState, useEffect, useCallback } from 'react';
+import { GiftedChat } from 'react-native-gifted-chat';
+import firebase from 'firebase';
+import { connect } from 'react-redux'
+import { bindActionCreators } from 'redux'
+import { fetchUser } from '../../redux/actions/index'
+
+export function RoomScreen({ route }) {
+  const { thread } = route.params;
+  const [messages, setMessages] = useState([])
+
+  useEffect(() => {
+    const unsubscribe = firebase.firestore() 
+    .collection('THREADS')
+    .doc(thread._id)
+    .collection('MESSAGES')
+    .onSnapshot(querySanpshot => {
+      const messageFirestore = querySanpshot
+        .docChanges() //para traer solo lo que haya cambiado
+        .filter(({ type }) => type == 'added') //el objeto tiene un prop added, ese es el que queremos
+        .map(({ doc }) => {
+          const message = doc.data()
+          return { ...message, createdAt: new Date().getTime() }
+        })
+        .sort((a, b) => b.createdAt - a.createdAt)
+    appendMessages(messageFirestore) //Para meter el mensaje en el estado messages
+    })
+    return () => unsubscribe()
+  }, [])
+
+
+  const appendMessages = useCallback((messages) => {
+    setMessages((previousMessages) => GiftedChat.append(previousMessages, messages))
+  }, [messages])
+
+  async function handleSend(messages) {
+    const writes = messages.map(m => firebase.firestore() 
+    .collection('THREADS')
+    .doc(thread._id)
+    .collection('MESSAGES').add(m))
+    await Promise.all(writes)
+  }
+
+  
+
+  return (
+    <GiftedChat messages={messages} user={{ _id: 1 }} onSend={handleSend} />
+  );
+}
+
+
+const mapStateToProps = (store) => ({
+  currentUser: store.userState.currentUser,
+})
+const mapDispatchProps = (dispatch) => bindActionCreators({fetchUser}, dispatch);
+export default connect(mapStateToProps, mapDispatchProps)(RoomScreen);