Update docs

Author: demchenkoalex

doc/firebase-cloud-functions.md

@@ -3,55 +3,55 @@ id: firebase-cloud-functions
 title: Cloud Functions
 ---
 
-This is an example of a cloud function that sets a message's status to delivered once the message is received on Firebase.
+This is an example of a cloud function that sets a message's status to `delivered` once the message is received on Firebase.
 
 ```js
-const functions = require("firebase-functions");
+const functions = require('firebase-functions')
 
 exports.changeMessageStatus = functions.firestore
-    .document("rooms/{roomId}/messages/{messageId}")
-    .onWrite((change) => {
-      const message = change.after.data();
-      if (message) {
-        if (["delivered", "read"].includes(message.status)) {
-          return null;
-        } else {
-          return change.after.ref.update({
-            status: "delivered",
-          });
-        }
+  .document('rooms/{roomId}/messages/{messageId}')
+  .onWrite((change) => {
+    const message = change.after.data()
+    if (message) {
+      if (['delivered', 'seen', 'sent'].includes(message.status)) {
+        return null
       } else {
-        return null;
+        return change.after.ref.update({
+          status: 'delivered',
+        })
       }
-    });
+    } else {
+      return null
+    }
+  })
 ```
 
-This is an example of a cloud function that sets a room's `lastMessage` to the most recent message sent once recieved in Firestore.
+This is an example of a cloud function that sets room's `lastMessages` to the most recent message sent once recieved in Firestore.
 
 ```js
-const functions = require("firebase-functions");
-const admin = require("firebase-admin");
+const admin = require('firebase-admin')
+const functions = require('firebase-functions')
 
-admin.initializeApp();
+admin.initializeApp()
 
-const db = admin.firestore();
+const db = admin.firestore()
 
 exports.changeLastMessage = functions.firestore
-    .document("rooms/{roomId}/messages/{messageId}")
-    .onUpdate((change, context) => {
-      const message = change.after.data();
-      if (message) {
-        return db.doc("rooms/" + context.params.roomId).update({
-          lastMessage: message,
-        });
-      } else {
-        return null;
-      }
-    });
+  .document('rooms/{roomId}/messages/{messageId}')
+  .onUpdate((change, context) => {
+    const message = change.after.data()
+    if (message) {
+      return db.doc('rooms/' + context.params.roomId).update({
+        lastMessages: [message],
+      })
+    } else {
+      return null
+    }
+  })
 ```
 
 :::important
 
-Starting from March 15, 2021, you will need a paid plan to use Cloud Functions, so there might be a better way to do it. We will explore options to create more examples, including `read` status and push notifications.
+Starting from March 15, 2021, you will need a paid plan to use Cloud Functions, so there might be a better way to do it. We might explore options to create more examples, including `seen` status and push notifications.
 
 :::