Using Node.js to build a command-line interface (CLI)

Using Node.js to build a command-line interface (CLI)

A command-line interface (CLI) is a text-based user interface (UI) for running programs, managing files, and interacting with computers. Building your own CLI is easier than you might think with Node.js

Node.js is a powerful JavaScript runtime that allows developers to build fast and scalable network applications.One of the many benefits of using Node.js is its ability to build command-line interfaces (CLIs) that can be used to automate repetitive tasks and perform various operations on the command line. In this article, we will explore how to use Node.js to build a simple CLI application.

A command-line interface (CLI) is a means of interacting with a computer program by typing commands to it and receiving text-based output in return. Building a CLI with Node.js allows for a wide range of possibilities, as Node.js provides a powerful and flexible JavaScript runtime environment that can be used to create a variety of different types of applications.

A CLI is a program which a user interacts within a terminal. CLI utilities are mostly used by people from Internet Technologies industry — Software Engineers, DevOps and c.

Benifits of CLI :

  • CLIs` main goal is to simplify different tasks by automating and encapsulating operations into small commands.
  • By performing, wrapping, and combining commands in the terminal a developer can sufficiently enhance everyday working experience and speed up a development process.
  • With Node.js a process of making the CLI application is fast, easy, and fun because of many reasons. To start with JavaScript, which is one of the most popular programming languages in the world. It is everywhere — in browsers, server-side, devices, and cloud. JavaScript dynamic nature facilitates project extension and plug-in capabilities.
  • The other benefit of creating the CLI application in Node.js technology is NPM — a brilliant built-in tool allowing to organise code in packages. An enormous community allows to adapt and reuse libraries written for all possible purposes.
  • Rich modules infrastructure helps developers to focus more on their application logic and makes Node.js shine in prototyping, which is highly important to prove ideas nowadays when time to market (TTM) is one of the most significant values.

One of the first steps in building a CLI with Node.js is to choose a package that can be used to create the command-line interface. There are several popular packages available, including "commander," "inquirer," and "yargs." Each of these packages has its own strengths and weaknesses, so it is important to choose the one that best fits the needs of the specific application.

To get started, you will need to have Node.js installed on your system. You can download the latest version of Node.js from the official website. Once you have Node.js installed, you can use the npm package manager to install the necessary modules and dependencies for your application.

The first step in building a CLI with Node.js is to create a new project directory and initialize it with npm. To do this, open a terminal and navigate to the directory where you want to create your project. Then, run the following command:

 

npm init -y


This command will create a new package.json file in your project directory, which will contain all the necessary information about your project, including the dependencies and scripts that you will use.

Next, you will need to install a module called commander which is a popular Node.js module for building CLIs. You can install it by running the following command:

npm install commander


Once the module is installed, you can start building your CLI. The first step is to import the commander module into your application:

 

const program = require('commander');


With the commander module imported, you can now define the commands and options that your CLI will support. For example, you can create a command called "greet" that will print a greeting message to the console when executed. To do this, you can use the command method of the commander module:

 

program
  .command('greet')
  .description('Print a greeting message')
  .action(() => {
    console.log('Hello World!');
  });


In addition to the command method, you can also use the option method to define options that can be passed to your commands. For example, you can create an option called "name" that will allow the user to specify their name when running the "greet" command:

const program = require('commander');

function greet(name) {
  console.log(`Hello, ${name}!`);
}

function add(num1, num2) {
  console.log(`The sum is: ${num1 + num2}`);
}

program
  .version('0.1.0')
  .description('A simple command-line interface')
  .command('greet <name>', 'greet the user', greet)
  .command('add <num1> <num2>', 'add two numbers', add)
  .parse(process.argv);



Once you have defined your commands and options, you can use the parse method of the commander module to parse the command line arguments and execute the appropriate action:

program.parse(process.argv);


The above code will parse the command line arguments and execute the action associated with the command that the user has entered.

In the above code, we are defining two commands: greet and add. The greet command takes one argument, name, while the add command takes two arguments, num1 and num2. We are also defining the version and description of our CLI using the version and description methods.

To handle these commands, we will create two separate functions for each command. These functions will be passed as the second argument to the command method.

const program = require('commander');

 function greet(name) {
 console.log(`Hello, ${name}!`); 
} 

function add(num1, num2) { 
console.log(`The sum is: ${num1 + num2}`); 
} 

program .version('0.1.0') .
description('A simple command-line interface') .
command('greet <name>', 'greet the user', greet) .
command('add <num1> <num2>', 'add two numbers', add) .
parse(process.argv);

Now, if we run our CLI and pass the greet command followed by a name, it will print "Hello, [name]!" to the console. Similarly, if we run the add command followed by two numbers, it will print "The sum is: [sum]" to the console.

The CLI's stability and reliability are genuine benefits in any IT Organization where administrators deal with frequent application patches and updates. CLIs also demand little system overhead, and they lack audiovisual frills or graphical blandishments that require excess resources or network bandwidth.

One of such ecommerce development company in delhi is scrrum labs located in New Delhi which uses NodeJs .Scrrum Labs is a fast expanding IT service company dedicated to partnering with you on your journey to being future-ready. 

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