created functions retrieving all topics

functions/handlers/topic.js

@@ -0,0 +1,35 @@
+/* eslint-disable promise/always-return */
+const admin = require('firebase-admin');
+exports.putTopic = (req, res) => {
+
+    const newTopic = {
+        topic: req.body.topic
+    };
+
+    admin.firestore().collection('topics').add(newTopic)
+    .then((doc) => {
+        const resTopic = newTopic;
+        return res.status(200).json(resTopic);
+    })
+    .catch((err) => {
+        console.error(err);
+        return res.status(500).json({ error: 'something is wrong'});
+    });
+};
+
+
+
+exports.getAllTopics = (req, res) => {
+    admin.firestore().collection('topics').get()
+    .then((data) => {
+        let topics = [];
+        data.forEach(function(doc) {
+            topics.push(doc.data());
+        });
+        return res.status(200).json(topics);
+    })
+    .catch((err) => {
+        console.error(err);
+        return res.status(500).json({error: 'Failed to fetch all posts written by specific user.'})
+    })
+};

functions/index.js

@@ -55,11 +55,13 @@ app.post("/putPost", fbAuth, putPost);
 /*------------------------------------------------------------------*
  *  handlers/topic.js                                                *
  *------------------------------------------------------------------*/
-const { putTopic 
+const { putTopic, getAllTopics
 } = require("./handlers/topic");
 
 // add topic to database
-
 app.post("/putTopic", fbAuth, putTopic);
 
+// get all topics from database
+app.get("/getAllTopics", fbAuth, getAllTopics);
+
 exports.api = functions.https.onRequest(app);