Slack Clone App

9min
React Slack Clone App
Introduction
In this guide, we will keep exploring the Parse React hook in useful situations by creating a Slack Clone App. The App will have basic features such as signup/login, channels, and real-time chat. In addition, the React components highlight the usefulness of real-time notifications using Live Query, User management capabilities, and the flexibility to perform queries (relational).
At any moment you can quickly deploy a slack clone app on Vercel:
Deploy
﻿
Prerequisites
To complete this tutorial, you will need:
An Back4App free account.
Clone or download this project via our GitHub repositories so you can run it along with the guide. Make sure to follow the instructions on the README file to successfully set it up in your local environment:
﻿JavaScript Example Repository
﻿
﻿TypeScript Example Repository﻿
Goal
To build a Slack clone application on React using the @parse/react hook.
- Creating your Parse app from a template
This application comprises two database classes: Channel and Message, containing pointers to the Parse User class. Instead of creating the app and database classes from scratch, let’s clone an existing template at Back4App Database Hub. Click on the “Clone Database” button and proceed with logging in and creating your app. For more details on how to clone please check the clone App guide.
﻿
Now your App has the complete backend structure necessary to create your Slack Clone on Back4App.
- Enabling Live Query
Now that you have created the App and classes, you need to enable the live query(real-time). Go to your Back4App dashboard and navigate to App Settings > Server Settings > Server URL and Live Query. After activating your Back4App subdomain, you can then activate Live Query by selecting the classes Message and Channel. After that, save the changes.
﻿
The URL above is your Live Query URL make sure to copy it in order to properly initialize the Parse hook.
Let’s now dive into the core React components: ChannelList, MessageList, and Home.
- The List components
The ChannelList and MessageList components use the @parse/react hook to retrieve the User data through Live Query. They have the same pattern structure as in the React LiveChat guide. They are instantiated with initial parameters (retrieved via the props object) that dynamically compose their Live Query query. Take a look at their queries and how the classes are related to each other:
JavaScript
TypeScript
// Note that Parse.Object coming from props need to be changed into pointers
// to be able to be used by Parse, since React changes the object structure
// when passing down parameters to child components

// channelList.js

const ownerQuery = new Parse.Query("Channel");
ownerQuery.equalTo("owner", props.currentUser.toPointer());
const membersQuery = new Parse.Query("Channel");
membersQuery.containedIn("members", [props.currentUser.toPointer()]);
// Creates the OR query
const parseQuery = Parse.Query.or(ownerQuery, membersQuery);
// Set results ordering
parseQuery.ascending("name");
// Include all pointer fields
parseQuery.includeAll();

// messageList.js

const parseQuery = new Parse.Query("Message");
// Get messages that involve both nicknames
parseQuery.equalTo("channel", props.currentChannel.toPointer());
// Set results ordering
parseQuery.ascending("createdAt");
// Include nickname fields, to enable name getting on list
parseQuery.includeAll();
// Note that Parse.Object coming from props need to be changed into pointers
// to be able to be used by Parse, since React changes the object structure
// when passing down parameters to child components

// channelList.js

const ownerQuery = new Parse.Query("Channel");
ownerQuery.equalTo("owner", props.currentUser.toPointer());
const membersQuery = new Parse.Query("Channel");
membersQuery.containedIn("members", [props.currentUser.toPointer()]);
// Creates the OR query
const parseQuery = Parse.Query.or(ownerQuery, membersQuery);
// Set results ordering
parseQuery.ascending("name");
// Include all pointer fields
parseQuery.includeAll();

// messageList.js

const parseQuery = new Parse.Query("Message");
// Get messages that involve both nicknames
parseQuery.equalTo("channel", props.currentChannel.toPointer());
// Set results ordering
parseQuery.ascending("createdAt");
// Include nickname fields, to enable name getting on list
parseQuery.includeAll();
﻿
These queries will be running every time there is a change in the classes data, so if another user in the channel sends a message, you will see it appearing there in real-time.
- The Home component
The Home component acts as the main application screen, in which the list components are conditionally rendered and instantiated when needed. You can find below the component code. Take a look at the functions for creating channels and inviting users to them.
Home.js
Home.tsx
import React, { useEffect, useState } from "react";
import "./App.css";
import { Modal } from "antd";
import { useHistory } from "react-router-dom";
import Parse from "parse";
import { ChannelList } from "./ChannelList";
import { MessageList } from "./MessageList";
import { MemberList } from "./MemberList";

export const Home = () => {
 const history = useHistory();

 // State variables holding input values and flags
 const [currentUser, setCurrentUser] = useState(null);
 const [isCreateChannelModalVisible, setIsCreateChannelModalVisible] =
   useState(false);
 const [createChannelInput, setCreateChannelInput] = useState("");
 const [currentChannel, setCurrentChannel] = useState(null);

 // This effect hook runs at every render and checks if there is a
 // logged in user, redirecting to Login screen if needed
 useEffect(() => {
   const checkCurrentUser = async () => {
     try {
       const user = await Parse.User.currentAsync();
       if (user === null || user === undefined) {
         history.push("/");
       } else {
         if (currentUser === null) {
           setCurrentUser(user);
         }
       }
       return true;
     } catch (_error) {}
     return false;
   };
   checkCurrentUser();
 });

 // Logout function
 const doLogout = async () => {
   // Logout
   try {
     await Parse.User.logOut();
     // Force useEffect execution to redirect back to Login
     setCurrentUser(null);
     return true;
   } catch (error) {
     alert(error);
     return false;
   }
 };

 // Makes modal visible
 const showCreateChannelModal = () => {
   setIsCreateChannelModalVisible(true);
 };

 // Clear input and hide modal on cancel
 const handleCreateChannelModalCancel = () => {
   setCreateChannelInput("");
   setIsCreateChannelModalVisible(false);
 };

 // Creates a channel based on input from modal
 const doCreateChannel = async () => {
   const channelName = createChannelInput;

   if (channelName === "") {
     alert("Please inform your new channel name!");
     return false;
   }

   // Creates a new Parse.Object instance and set parameters
   const Channel = new Parse.Object("Channel");
   Channel.set("name", channelName);
   Channel.set("owner", currentUser);
   // Members is an array of Parse.User objects, so .add() should be used to
   // concatenate the value inside the array
   Channel.add("members", currentUser);

   // Clears input value and hide modal
   setCreateChannelInput("");
   setIsCreateChannelModalVisible(false);

   try {
     // Save object on Parse server
     const saveResult = await Channel.save();
     // Set the created channel as the active channel,
     // showing the message list for this channel
     setCurrentChannel(saveResult);
     alert(`Success on creating channel ${channelName}`);
     return true;
   } catch (error) {
     alert(error);
     return false;
   }
 };

 // Changes the active channel and shows the message list for it
 // This is called using a callback in the ChannelList component
 const doSelectChannel = (channel) => {
   setCurrentChannel(null);
   setCurrentChannel(channel);
 };

 // Settings current channel to null hides the message list component
 // This is called using a callback in the MessageList component
 const doClearCurrentChannel = () => {
   setCurrentChannel(null);
 };

 return (
   <div className="grid">
     <div className="organizations">
       <div className="organization">
         <picture className="organization__picture">
           <img
             className="organization__img"
             src="https://scontent.fsqx1-1.fna.fbcdn.net/v/t1.6435-9/29136314_969639596535770_8356900498426560512_n.png?_nc_cat=103&ccb=1-5&_nc_sid=973b4a&_nc_ohc=D9actPSB8DUAX-zaA7F&_nc_ht=scontent.fsqx1-1.fna&oh=96679a09c5c4524f0a6c86110de697b6&oe=618525F9"
             alt=""
           />
         </picture>
         <p className="organization__title">Back4App</p>
       </div>
       <button className="button-inline" onClick={doLogout}>
         <svg
           className="button-inline__icon"
           xmlns="http://www.w3.org/2000/svg"
           width="24"
           height="24"
           viewBox="0 0 24 24"
           fill="none"
           stroke="currentColor"
           strokeWidth="2"
           strokeLinecap="round"
           strokeLinejoin="round"
         >
           <polyline points="9 10 4 15 9 20"></polyline>
           <path d="M20 4v7a4 4 0 0 1-4 4H4"></path>
         </svg>
         <span className="button-inline__label">Log out</span>
       </button>
     </div>
     <div className="channels">
       {/* Action buttons (new channel and logout) */}
       <div>
         <Modal
           title="Create new channel"
           visible={isCreateChannelModalVisible}
           onOk={doCreateChannel}
           onCancel={handleCreateChannelModalCancel}
           okText={"Create"}
         >
           <>
             <label>{"Channel Name"}</label>
             <input
               type={"text"}
               value={createChannelInput}
               placeholder={"New Channel Name"}
               onChange={(event) => setCreateChannelInput(event.target.value)}
             ></input>
           </>
         </Modal>
       </div>
       <div className="channels-header" onClick={showCreateChannelModal}>
         <p className="channels-header__label">Channels</p>
         <svg
           className="channels-header__icon"
           xmlns="http://www.w3.org/2000/svg"
           height="24px"
           viewBox="0 0 24 24"
           width="24px"
           fill="#000000"
         >
           <path d="M0 0h24v24H0z" fill="none" />
           <path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z" />
         </svg>
       </div>
       {/* Channel list component, instantiated only when the user is successfully fetched */}
       {currentUser !== null && (
         <ChannelList
           currentUser={currentUser}
           selectChannelCallback={doSelectChannel}
         />
       )}
     </div>
     <div className="messages">
       {/* Message list component, instantiated only when there is a selected channel */}
       {currentUser !== null && currentChannel !== null && (
         <MessageList
           currentUser={currentUser}
           currentChannel={currentChannel}
           closeChannelCallback={doClearCurrentChannel}
         />
       )}
     </div>
     <div className="info">
       {/* Member list component, instantiated only when there is a selected channel */}
       {currentUser !== null && currentChannel !== null && (
         <MemberList
           currentUser={currentUser}
           currentChannel={currentChannel}
           closeChannelCallback={doClearCurrentChannel}
         />
       )}
     </div>
   </div>
 );
};
import React, { useEffect, useState } from "react";
import "./App.css";
import { Modal } from "antd";
import { useHistory } from "react-router-dom";
import Parse from "parse";
import { ChannelList } from "./ChannelList";
import { MessageList } from "./MessageList";
import { MemberList } from "./MemberList";

export const Home = () => {
 const history = useHistory();

 // State variables holding input values and flags
 const [currentUser, setCurrentUser] = useState(null);
 const [isCreateChannelModalVisible, setIsCreateChannelModalVisible] =
   useState(false);
 const [createChannelInput, setCreateChannelInput] = useState("");
 const [currentChannel, setCurrentChannel] = useState(null);

 // This effect hook runs at every render and checks if there is a
 // logged in user, redirecting to Login screen if needed
 useEffect(() => {
   const checkCurrentUser = async () => {
     try {
       const user = await Parse.User.currentAsync();
       if (user === null || user === undefined) {
         history.push("/");
       } else {
         if (currentUser === null) {
           setCurrentUser(user);
         }
       }
       return true;
     } catch (_error) {}
     return false;
   };
   checkCurrentUser();
 });

 // Logout function
 const doLogout = async () => {
   // Logout
   try {
     await Parse.User.logOut();
     // Force useEffect execution to redirect back to Login
     setCurrentUser(null);
     return true;
   } catch (error) {
     alert(error);
     return false;
   }
 };

 // Makes modal visible
 const showCreateChannelModal = () => {
   setIsCreateChannelModalVisible(true);
 };

 // Clear input and hide modal on cancel
 const handleCreateChannelModalCancel = () => {
   setCreateChannelInput("");
   setIsCreateChannelModalVisible(false);
 };

 // Creates a channel based on input from modal
 const doCreateChannel = async () => {
   const channelName = createChannelInput;

   if (channelName === "") {
     alert("Please inform your new channel name!");
     return false;
   }

   // Creates a new Parse.Object instance and set parameters
   const Channel = new Parse.Object("Channel");
   Channel.set("name", channelName);
   Channel.set("owner", currentUser);
   // Members is an array of Parse.User objects, so .add() should be used to
   // concatenate the value inside the array
   Channel.add("members", currentUser);

   // Clears input value and hide modal
   setCreateChannelInput("");
   setIsCreateChannelModalVisible(false);

   try {
     // Save object on Parse server
     const saveResult = await Channel.save();
     // Set the created channel as the active channel,
     // showing the message list for this channel
     setCurrentChannel(saveResult);
     alert(`Success on creating channel ${channelName}`);
     return true;
   } catch (error) {
     alert(error);
     return false;
   }
 };

 // Changes the active channel and shows the message list for it
 // This is called using a callback in the ChannelList component
 const doSelectChannel = (channel) => {
   setCurrentChannel(null);
   setCurrentChannel(channel);
 };

 // Settings current channel to null hides the message list component
 // This is called using a callback in the MessageList component
 const doClearCurrentChannel = () => {
   setCurrentChannel(null);
 };

 return (
   <div className="grid">
     <div className="organizations">
       <div className="organization">
         <picture className="organization__picture">
           <img
             className="organization__img"
             src="https://scontent.fsqx1-1.fna.fbcdn.net/v/t1.6435-9/29136314_969639596535770_8356900498426560512_n.png?_nc_cat=103&ccb=1-5&_nc_sid=973b4a&_nc_ohc=D9actPSB8DUAX-zaA7F&_nc_ht=scontent.fsqx1-1.fna&oh=96679a09c5c4524f0a6c86110de697b6&oe=618525F9"
             alt=""
           />
         </picture>
         <p className="organization__title">Back4App</p>
       </div>
       <button className="button-inline" onClick={doLogout}>
         <svg
           className="button-inline__icon"
           xmlns="http://www.w3.org/2000/svg"
           width="24"
           height="24"
           viewBox="0 0 24 24"
           fill="none"
           stroke="currentColor"
           strokeWidth="2"
           strokeLinecap="round"
           strokeLinejoin="round"
         >
           <polyline points="9 10 4 15 9 20"></polyline>
           <path d="M20 4v7a4 4 0 0 1-4 4H4"></path>
         </svg>
         <span className="button-inline__label">Log out</span>
       </button>
     </div>
     <div className="channels">
       {/* Action buttons (new channel and logout) */}
       <div>
         <Modal
           title="Create new channel"
           visible={isCreateChannelModalVisible}
           onOk={doCreateChannel}
           onCancel={handleCreateChannelModalCancel}
           okText={"Create"}
         >
           <>
             <label>{"Channel Name"}</label>
             <input
               type={"text"}
               value={createChannelInput}
               placeholder={"New Channel Name"}
               onChange={(event) => setCreateChannelInput(event.target.value)}
             ></input>
           </>
         </Modal>
       </div>
       <div className="channels-header" onClick={showCreateChannelModal}>
         <p className="channels-header__label">Channels</p>
         <svg
           className="channels-header__icon"
           xmlns="http://www.w3.org/2000/svg"
           height="24px"
           viewBox="0 0 24 24"
           width="24px"
           fill="#000000"
         >
           <path d="M0 0h24v24H0z" fill="none" />
           <path d="M19 13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z" />
         </svg>
       </div>
       {/* Channel list component, instantiated only when the user is successfully fetched */}
       {currentUser !== null && (
         <ChannelList
           currentUser={currentUser}
           selectChannelCallback={doSelectChannel}
         />
       )}
     </div>
     <div className="messages">
       {/* Message list component, instantiated only when there is a selected channel */}
       {currentUser !== null && currentChannel !== null && (
         <MessageList
           currentUser={currentUser}
           currentChannel={currentChannel}
           closeChannelCallback={doClearCurrentChannel}
         />
       )}
     </div>
     <div className="info">
       {/* Member list component, instantiated only when there is a selected channel */}
       {currentUser !== null && currentChannel !== null && (
         <MemberList
           currentUser={currentUser}
           currentChannel={currentChannel}
           closeChannelCallback={doClearCurrentChannel}
         />
       )}
     </div>
   </div>
 );
};
﻿
This approach of dynamically instantiating the Live Query components allows us to reuse them whenever the user changes the active channel, creates a new one, sends a message, etc. Here is how the complete App will look.
﻿
- Deploy on Vercel
At any time you can deploy the application on vercel by clicking on the link below:
Deploy
﻿
Make sure you have your Application ID, Client Key and LiveQuery URL. For the keys you can go to App Settings -> Security & Keys and then copy. For the Live Query URL you can go to Step 2 and copy it.
Conclusion
At the end of this guide, you learned more about using the Parse React hook for live queries in Parse and how to use Back4App’s Database Hub.