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Install And Setup React App on Ubuntu

React is a JavaScript library for building user interfaces. It is opensource and maintained by Facebook.You can read more about React here.In this blog we are going to learn how to install and setup a React App on Ubuntu (version 16 and above).PrerequisitesThis blog assumes that you are using Ubuntu 16 or above versions and you have all the privileges to install the software in the machine, and also have access to the required websites mentioned in the blog.System Requirements:Ubuntu 16 or aboveMinimum 4GB RAMVisual Studio Code installed.Why should we choose React, and what are its advantages?React is built on JavaScript which makes it easier to learn and easier to use.React is component based which means we can write re-usable components. Start with small things, which you use to build bigger things, which you use to build apps.React is lightweight compared to Angular; which in turn makes your application faster to load—which is very important from the user’s point of view.React ensures faster rendering of DOM (document object model), this has been achieved by the introduction of Virtual DOM-currently, one of the benefits of using React for heavy loaded and dynamic software solutions.React has a helpful and interactive developer toolset which makes it easy to debug. React Developer Tools is a browser extension available for both Chrome and Firefox. It enables developers to observe reactive component hierarchies, discover child and parent components, and inspect their current state and props.  React uses JSX(JavaScript XML) which has HTML-like syntax, making it easy to code and understand.React has strong community support on Github, Stackoverflow and many other platforms.React is SEO friendly.There are certainly many other nice features about using React.What is Node.js?Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js is an Open Source Server Environment that is free and runs on almost all Operating Systems (Windows, Linux, Unix, Mac OS X, etc.).You can read more about Nodejs here.Why do we need Nodejs for React apps?Node.js lets developers use JavaScript to develop variety of applications like network applications, command line tools, web APIs, mobile applications, web applications etc.React usually runs on Node Server in development, but we can make use of other Servers likes Apache or Nginix to run React App in production. You do not need NodeJS to run React in production.What is NPM, why do we need NPM for React apps?NPM (Node Package Manager) is a dependency management tool for JavaScript applications. It is Open Source and also has command line utility for interacting with the application that aids in package installation, version management, and dependency management.React does not ship with all the features by itself, so it uses external packages to add the required features to the React application. These packages are maintained by NPM (Node package manager) which is shipped with Nodejs in development.You can read more about npm here.We can use yarn instead of NPM during development and production for React apps.Install Node.jsThere are many ways to install Node.js in an Ubuntu machine.Install Node.js from the Ubuntu repositoryInstall Using a PPA (personal package archive)Using the first method we will not get the latest version of Node.js installed so we will choose the second method where we will get the latest version of Node.js installed.Installing Using a PPA (personal package archive)To get the latest version of Node.js installed on ubuntu, add a PPA (personal package archive). It is maintained by NodeSource.Open terminal and run below commands:Install curl: Run below command on terminalCommand: sudo apt-get install curlSet the NodeSource PPA: Run below command on terminalCommand: curl -sL https://deb.nodesource.com/setup_current.x | sudo -E bash –The PPA will be added to your configuration and your local package cache will be updated automatically.You can read more about available versions of Node.js in nodesource here.Install Node.js: Run the below command on terminalCommand: sudo apt-get install -y nodejsCheck for Node.js Installation: Run below command on terminalCommand: node -vIt has to show the version of node installed in this case v15.4.0Now let's see how we can install and setup React app in Ubuntu machineUsing create-react-app (installing create-react-app using npm)Using npx (Recommended in React docs)Using create-react-app (npm)In setting up a React project we come across tools like babel and webpack which are not easy to understand and configure for a person who is new to React and JavaScript. There are several tools that help to sort this problem. One of them is create-react-app. This is the easiest to setup. Create-react-app comes with production grade configurations pre-built. You can alter the configurations by ejecting from the create-react-app as well.Follow the below steps to install using npm create-react-appGo into your desired location where you want to start your react app using ‘cd’ command Run below command to install create-react-app using npm Command: npm install -g create-react-appNow Run create-react-app on terminal to setup a React-app. Command: create-react-app hello-worldThis creates a folder with the name hello-world. You can navigate into the folder using ‘cd’ command and look at the project structure.This gives the React app which we can use, but React recommends using npx.Using npx command:npx is the package runner, since npm version 5.2.0 npx is pre-bundled with npm.Read more about differences npx and npm here.Follow the below steps to setup using npx.Go into your desired location where you want to start your react app using ‘cd’ commandRun the below command to setup React app using npxCommand: npx create-react-app my-appThat’s it! Your React app is ready with a single command.This creates a folder with the name hello-world. You can navigate into the folder using ‘cd’ command.  Now open the project in vs-codeWhen you open the project in visual studio code the structure looks like this.Now let's have a look at the files and folders we have:node_modules: This folder is managed by package manager (npm) and contains all the project library dependencies. We should not edit any file inside this folder.public: This folder contains the assets that should be served publicly without any restrictions and contains files like index.html, favicon, manifest.jsonsrc:  This is the folder that contains all the files that are used to create web applications. As a react developer you are likely to spend a lot of time in this folder creating components and other sources of code..gitignore: This file has all the assets which should be ignored by git while we publish our code to GitHub eg: node_modulespackage.json: This is a JSON file which has all information about the app such as name, dependencies, scripts we use to run the application etc.Readme.md: This is a markdown file where you specify the things which you want to show when someone visits your project on GitHub.Now let's run our first React app!Open the terminal integrated with Visual studio code or just stay in the ubuntu terminal; either is fine. Let's use the integrated terminal.Run the app using the following command: Command: npm startThis opens the app in your favourite browser as shown below:Now, let's make our first code changes:On navigating to src folder, you will find App.js file, through which the whole app is run inside the browser. Change the code as you see below and save by hitting ctrl+s.Now look at the browser where the app is running. It looks like the one in the image below.Congratulations on making your first React app!What you have learnt:What is React and why it should be usedWhat is Node.js, and how it should be installed on Ubuntu.What is npmWhat is create-react-appHow to setup React-app on UbuntuHow to run the React-app  How to make code changes to create your first React application.React has rapid changes for every new version. It is important to keep yourself updated with the latest releases of React, so that you can make your life as a React developer easier!

Install And Setup React App on Ubuntu

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Install And Setup React App on Ubuntu

React is a JavaScript library for building user interfaces. It is opensource and maintained by Facebook.

You can read more about React here.

In this blog we are going to learn how to install and setup a React App on Ubuntu (version 16 and above).

Prerequisites

This blog assumes that you are using Ubuntu 16 or above versions and you have all the privileges to install the software in the machine, and also have access to the required websites mentioned in the blog.

System Requirements:

  • Ubuntu 16 or above
  • Minimum 4GB RAM
  • Visual Studio Code installed.

Why should we choose React, and what are its advantages?

  • React is built on JavaScript which makes it easier to learn and easier to use.
  • React is component based which means we can write re-usable components. Start with small things, which you use to build bigger things, which you use to build apps.
  • React is lightweight compared to Angular; which in turn makes your application faster to load—which is very important from the user’s point of view.
  • React ensures faster rendering of DOM (document object model), this has been achieved by the introduction of Virtual DOM-currently, one of the benefits of using React for heavy loaded and dynamic software solutions.
  • React has a helpful and interactive developer toolset which makes it easy to debug. React Developer Tools is a browser extension available for both Chrome and Firefox. It enables developers to observe reactive component hierarchies, discover child and parent components, and inspect their current state and props.  
  • React uses JSX(JavaScript XML) which has HTML-like syntax, making it easy to code and understand.
  • React has strong community support on Github, Stackoverflow and many other platforms.
  • React is SEO friendly.

There are certainly many other nice features about using React.

What is Node.js?

Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js is an Open Source Server Environment that is free and runs on almost all Operating Systems (Windows, Linux, Unix, Mac OS X, etc.).

You can read more about Nodejs here.

Why do we need Nodejs for React apps?

Node.js lets developers use JavaScript to develop variety of applications like network applications, command line tools, web APIs, mobile applications, web applications etc.

React usually runs on Node Server in development, but we can make use of other Servers likes Apache or Nginix to run React App in production. You do not need NodeJS to run React in production.

What is NPM, why do we need NPM for React apps?

NPM (Node Package Manager) is a dependency management tool for JavaScript applications. It is Open Source and also has command line utility for interacting with the application that aids in package installation, version management, and dependency management.

React does not ship with all the features by itself, so it uses external packages to add the required features to the React application. These packages are maintained by NPM (Node package manager) which is shipped with Nodejs in development.

You can read more about npm here.

We can use yarn instead of NPM during development and production for React apps.

Install Node.js

There are many ways to install Node.js in an Ubuntu machine.

  1. Install Node.js from the Ubuntu repository
  2. Install Using a PPA (personal package archive)

Using the first method we will not get the latest version of Node.js installed so we will choose the second method where we will get the latest version of Node.js installed.

Installing Using a PPA (personal package archive)

To get the latest version of Node.js installed on ubuntu, add a PPA (personal package archive). It is maintained by NodeSource.

Open terminal and run below commands:

  • Install curl: Run below command on terminal
    Command: sudo apt-get install curl

Install And Setup React App on Ubuntu

  • Set the NodeSource PPA: Run below command on terminal
    Command: curl -sL https://deb.nodesource.com/setup_current.x | sudo -E bash –

Install And Setup React App on Ubuntu

The PPA will be added to your configuration and your local package cache will be updated automatically.

You can read more about available versions of Node.js in nodesource here.

  • Install Node.js: Run the below command on terminal
    Command: sudo apt-get install -y nodejs

  • Check for Node.js Installation: Run below command on terminal
    Command: node -v
    It has to show the version of node installed in this case v15.4.0

Install And Setup React App on Ubuntu

Now let's see how we can install and setup React app in Ubuntu machine

  • Using create-react-app (installing create-react-app using npm)
  • Using npx (Recommended in React docs)

Using create-react-app (npm)

In setting up a React project we come across tools like babel and webpack which are not easy to understand and configure for a person who is new to React and JavaScript. There are several tools that help to sort this problem. One of them is create-react-app. This is the easiest to setup. Create-react-app comes with production grade configurations pre-built. You can alter the configurations by ejecting from the create-react-app as well.

Follow the below steps to install using npm create-react-app

  • Go into your desired location where you want to start your react app using ‘cd’ command 
  • Run below command to install create-react-app using npm 
    Command: npm install -g create-react-app

Install And Setup React App on Ubuntu

  • Now Run create-react-app on terminal to setup a React-app. 
    Command: create-react-app hello-world

Install And Setup React App on Ubuntu

  • This creates a folder with the name hello-world. You can navigate into the folder using ‘cd’ command and look at the project structure.

This gives the React app which we can use, but React recommends using npx.

Using npx command:

npx is the package runner, since npm version 5.2.0 npx is pre-bundled with npm.

Read more about differences npx and npm here.

Follow the below steps to setup using npx.

  • Go into your desired location where you want to start your react app using ‘cd’ command
  • Run the below command to setup React app using npx
    Command: npx create-react-app my-app
    That’s it! Your React app is ready with a single command.

Install And Setup React App on Ubuntu

  • This creates a folder with the name hello-world. You can navigate into the folder using ‘cd’ command.  
  • Now open the project in vs-code

When you open the project in visual studio code the structure looks like this.

Install And Setup React App on Ubuntu

Now let's have a look at the files and folders we have:

  • node_modules: This folder is managed by package manager (npm) and contains all the project library dependencies. We should not edit any file inside this folder.
  • public: This folder contains the assets that should be served publicly without any restrictions and contains files like index.html, favicon, manifest.json
  • src:  This is the folder that contains all the files that are used to create web applications. As a react developer you are likely to spend a lot of time in this folder creating components and other sources of code.
  • .gitignore: This file has all the assets which should be ignored by git while we publish our code to GitHub eg: node_modules
  • package.json: This is a JSON file which has all information about the app such as name, dependencies, scripts we use to run the application etc.
  • Readme.md: This is a markdown file where you specify the things which you want to show when someone visits your project on GitHub.

Now let's run our first React app!

  • Open the terminal integrated with Visual studio code or just stay in the ubuntu terminal; either is fine. Let's use the integrated terminal.
  • Run the app using the following command: 
    Command: npm start

Install And Setup React App on Ubuntu

This opens the app in your favourite browser as shown below:Install And Setup React App on Ubuntu

Now, let's make our first code changes:

On navigating to src folder, you will find App.js file, through which the whole app is run inside the browser. Change the code as you see below and save by hitting ctrl+s.

Install And Setup React App on Ubuntu

Now look at the browser where the app is running. It looks like the one in the image below.

Install And Setup React App on Ubuntu

Congratulations on making your first React app!

What you have learnt:

  • What is React and why it should be used
  • What is Node.js, and how it should be installed on Ubuntu.
  • What is npm
  • What is create-react-app
  • How to setup React-app on Ubuntu
  • How to run the React-app  
  • How to make code changes to create your first React application.

React has rapid changes for every new version. It is important to keep yourself updated with the latest releases of React, so that you can make your life as a React developer easier!

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Website : https://www.knowledgehut.com

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If we need to log the port on which the server is running, then we can get this info as well without hardcoding. server.listen(9000, () => {    console.log('opened server on %j', server.address().port);  }); The first parameter of listen is the port in which the server starts listening, and a callback which gets called once it has started listening. A few of the common errors raised are:  ERR_SERVER_ALREADY_LISTEN – server is already listening and hasn’t been closed. EADDRINUSE – another server is already listening on the given port/handle/path. Whenever an error happens, an ‘error’ event is raised. We can hook to it and capture the errors accordingly. server.on('error', (e) => {    if (e.code === 'EADDRINUSE') {      console.log('Address in use, retrying...');      setTimeout(() => {        server.close();        server.listen(PORT, HOST);      }, 1000);    }  }); Whenever a client connects to this server then a 'connection' event is raised and in the callback we can get hold of the client object for communicating data. server.on("connection", (socket) => {    console.log("new client connection is made");  }); The second parameter is actually a callback which has the reference to the connection object, and the client object is of type ‘net.Socket’. To get the details like address and port, we can rely on remoteAddress, and remotePort properties respectively.   server.on("connection", (socket) => {    console.log("Client connection details - ", socket.remoteAddress + ":" + socket.remotePort);  }); Let’s assume that we are developing an application server like bot which needs to take inputs from clients and respond to the client. We can get hold of the client object and send messages to it from the server. As soon as the client is connected, we can send a sample return message on successful connection. server.on("connection", (socket) => {    console.log("Client connection details - ", socket.remoteAddress + ":" + socket.remotePort);    socket.write('SERVER: Hello! Connection successfully made.');  }); Now if there is any data being sent by client, we can capture that data on the server by subscribing to ‘data’ event on the client socket object.  socket.on('data', (data) => {    console.log(data.toString());// since data is streamed in bytes, toString is used.  }); Some of the most commonly used events on ‘net.Socket’ are data, error and close. As the names suggest, data is for listening to any data sent, error when there is an error happens and close event is raised when a connection is closed which happens once. Here is an example in server.js file: const net = require('net');  var server = net.createServer();  server.on("connection", (socket) => {    console.log("new client connection is made", socket.remoteAddress + ":" + socket.remotePort);    socket.on("data", (data) => {      console.log(data.toString());    });    socket.once("close", () => {      console.log("client connection closed.");    });    socket.on("error", (err) => {      console.log("client connection got errored out.")    });    socket.write('SERVER: Hello! Connection successfully made.');  });  server.on('error', (e) => {    if (e.code === 'EADDRINUSE') {      console.log('Address in use, retrying...');      setTimeout(() => {        server.close();        server.listen(PORT, HOST);      }, 1000);    }    else {      console.log("Server failed.")    }  });  server.listen(9000, () => {    console.log('opened server on %j', server.address().port);  }); ‘net’ module also has another class type net.BlockList. This helps in controlling or disabling the inbound or outbound traffic based on rules from any specific IP addresses, IP ranges, or IP subnets. Here is an example snippet from the documentation: const blockList = new net.BlockList();  blockList.addAddress('123.123.123.123');  blockList.addRange('10.0.0.1', '10.0.0.10');  blockList.addSubnet('8592:757c:efae:4e45::', 64, 'ipv6');  console.log(blockList.check('123.123.123.123')); // Prints: true  console.log(blockList.check('10.0.0.3')); // Prints: true  console.log(blockList.check('222.111.111.222')); // Prints: false  // IPv6 notation for IPv4 addresses works:  console.log(blockList.check('::ffff:7b7b:7b7b', 'ipv6')); // Prints: true  console.log(blockList.check('::ffff:123.123.123.123', 'ipv6')); // Prints: true Now that we have the server up and running, we can build a client to connect to the server and start sending bi-directional data. This client could be another node.js application, java/c# application working with TCP sockets, asp.net MVC application talking to node.js TCP server or any other client application. But that client application should have TCP based communication mechanism support. Since we are talking about ‘net’ module, let’s build the client application as well using net module. Moreover, it supports TCP based communication as well. 'net’ module has a factory function called ‘createConnection’ which immediately creates a socket and establishes a connection with the server running on the specified port.  Let's create another client.js file and create a connection. const net = require('net');  const client = net.createConnection({ port: 9000 }, () => {    console.log('CLIENT: I connected to the server.');  }); The first parameter contains the details of the server. Since we are running the server locally, providing the port number would suffice for us as the host default address is localhost for TCP connections. The second parameter is the callback called once the connection is made successfully with the server. The returned value is of type net.Socket which we have learnt about earlier. Let’s hook to ‘data’ event and console log the information sent by the server. client.on('data', (data) => {    console.log(data.toString());    client.end();  }); Here we are not persisting the TCP connection and ending it once we receive a message from the server. We can subscribe to close event and handle any clean up needed. client.on('end', () => {    console.log('CLIENT: I disconnected from the server.');  }) The output on the client terminal has to be:  CLIENT: I connected to the server.  SERVER: Hello! This is server speaking.  CLIENT: I disconnected from the server. Output on server terminal will be: new client connection is made ::ffff:127.0.0.1:51680  CLIENT: Hello this is client!  client connection closed. In case we want to continue the client instance till the server is alive, we can comment out the ‘client.end()’ call. Any message in the terminal can be processed and sent to the server. For reading the text from terminal we use the readline module. Here is a complete example: const net = require('net');  const readline = require('readline');  const rl = readline.createInterface({    input: process.stdin,    output: process.stdout  });  const client = net.createConnection({ port: 9000 }, () => {  console.log('CLIENT: I connected to the server.');    client.write('CLIENT: Hello this is client!');  });  client.on('data', (data) => {    console.log(data.toString());    //client.end();  });  client.on('end', () => {    console.log('CLIENT: I disconnected from the server.');  })  rl.on('line', (input) => {    client.write(`CLIENT: ${input}`);  }); Both client and server now can communicate. When we type any text in client terminal, that is communicated to the server, and the server can respond back to the client via terminal.  ConclusionWebsockets help in creating a full-duplex connection for sending messages from client to server and vice-versa. Some of the real-time use cases that you may be familiar with are chat apps, IoT devices and so on. The Node.js net module helps you to create a server application easily, which can communicate to any type of client application like a web browser, mobile app, IoT device, Node.js client, or anything that knows TCP where the messaging need is bi-directional with streams. ‘net’ module can be used to communicate among child processes within a node.js server as well. 
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Node.Js - Net Module

Node.js has a ‘net’ module which provide... Read More