chat retrieval is done

stubs/api/chat/index.js

@@ -2,7 +2,7 @@ const chatRouter = require('express').Router();
 
 module.exports = chatRouter;
 
-const { getChatFromDB, getUsersChats, addChatToDB } = require('../db');
+const { getChatFromDB, getUsersChats, addChatToDB, getUserFromDB } = require('../db');
 
 chatRouter.get('/item/:id1/:id2', (req, res) => {
     const { id1, id2 } = req.params;
@@ -27,16 +27,20 @@ chatRouter.post('/item/:id1/:id2', (req, res) => {
         // Chat already exists
         res.status(200).send({chat});
     } else {
-        // Creating new chat
-        const newChat = {
-            id1: id1,
-            id2: id2,
-            messages: []
+        if (!getUserFromDB(id1) || !getUserFromDB(id2)) {
+            res.status(404).send({message: 'Such interlocutor does not exist'});
+        } else {
+            // Creating new chat
+            const newChat = {
+                id1: id1,
+                id2: id2,
+                messages: []
+            }
+
+            addChatToDB(newChat);
+
+            res.status(200).send({newChat});
         }
-
-        addChatToDB(newChat);
-
-        res.status(200).send({newChat});
     }
 })