Building CLI Applications Made Easy with These NodeJS Frameworks

Building a Command Line Interface (CLI) in NodeJS is a great way to create powerful tools that can be used from a terminal. There are many libraries and tools available to help you build a NodeJS CLI, each with their own strengths and weaknesses.

Here are some of the best tools to consider when building a NodeJS CLI:

1- Commander

Commander is one of the most popular NodeJS libraries for building CLIs. It provides a clean and simple API for defining and parsing command-line arguments. With Commander, you can easily add subcommands, options, and arguments to your CLI. It also includes support for generating help messages and version information.

Here’s an example of using Commander to create a simple CLI:

const { program } = require('commander');

program
  .version('1.0.0')
  .description('A command line tool')
  .option('-u, --username <username>', 'Your username')
  .option('-p, --password <password>', 'Your password')
  .parse(process.argv);

console.log('Username:', program.username);
console.log('Password:', program.password);

2- Inquirer

Inquirer is a powerful NodeJS library for creating interactive command-line interfaces. It allows you to create prompts and questions that the user can answer in the terminal. With Inquirer, you can easily create a wizard-style interface for your CLI, allowing the user to provide input in a more user-friendly way.

Here’s an example of using Inquirer to create a simple prompt:

const inquirer = require('inquirer');

inquirer
  .prompt([
    {
      type: 'input',
      name: 'username',
      message: "What's your username?"
    },
    {
      type: 'password',
      name: 'password',
      message: "What's your password?"
    }
  ])
  .then(answers => {
    console.log('Username:', answers.username);
    console.log('Password:', answers.password);
  });

3- Vorpal

Vorpal is a NodeJS framework for building interactive command-line tools. It provides a comprehensive set of features for building powerful CLI applications, including command auto-completion, history, and help messages. Vorpal also includes support for adding custom plugins and commands.

Here’s an example of using Vorpal to create a simple CLI:

const vorpal = require('vorpal')();

vorpal
  .command('greet <name>', 'Greet someone')
  .action(function (args, callback) {
    this.log(`Hello, ${args.name}!`);
    callback();
  });

vorpal.delimiter('cli$').show();

4- Oclif

Oclif is a framework for building CLI tools in NodeJS. It provides a robust set of features for building CLI applications, including command-line parsing, help messages, and error handling. Oclif also includes support for creating commands with subcommands, flags, and options.

Here’s an example of using Oclif to create a simple CLI:

$ npx oclif hello <name> [age]

import { Command, flags } from '@oclif/command';

class HelloCommand extends Command {
  static description = 'Say hello';

  static flags = {
    name: flags.string({ char: 'n', description: 'Name to greet' }),
  };

  async run() {
    const { flags } = this.parse(HelloCommand);
    const name = flags.name || 'world';
    this.log(`Hello, ${name}!`);
  }
}

export = HelloCommand;

5- Yargs

Yargs is a popular library for building CLI tools in NodeJS. It provides a simple and intuitive API for defining commands, options, and arguments. Yargs also includes support for generating help messages, and for parsing complex argument structures.

Here’s an example of using Yargs to create a simple CLI:

const yargs = require('yargs');

yargs
  .command({
    command: 'greet <name>',
    describe: 'Greet someone',
    builder: (yargs) => {
      return yargs.option('age', { describe: 'Age of the person', type: 'number' });
    },
    handler: (argv) => {
      console.log(`Hello, ${argv.name}! You are ${argv.age || 'unknown'} years old.`);
    }
  })
  .help()
  .argv;

6- Caporal

Caporal is a framework for building CLI applications in NodeJS. It provides a clean and simple API for defining commands and options, and includes support for generating help messages and for parsing complex argument structures.

Here’s an example of using Caporal to create a simple CLI:

const program = require('caporal');

program
  .version('1.0.0')
  .description('A command line tool')
  .command('greet', 'Greet someone')
  .argument('<name>', 'Name to greet')
  .option('--age <age>', 'Age of the person', program.INT)
  .action((args, options, logger) => {
    logger.info(`Hello, ${args.name}! You are ${options.age || 'unknown'} years old.`);
  });

program.parse(process.argv);

7- Gluegun

Gluegun is a lightweight framework for building CLI applications in NodeJS. It provides a simple and intuitive API for defining commands and options, and includes support for generating help messages and for parsing complex argument structures. Gluegun also includes support for creating custom plugins, and for generating boilerplate code for new commands.

Here’s an example of using Gluegun to create a simple CLI:

const { build } = require('gluegun');

async function run(argv) {
  const cli = build()
    .brand('my-cli')
    .src(__dirname)
    .plugins('./node_modules', { matching: 'my-cli-*', hidden: true })
    .create();

  const toolbox = await cli.run(argv);
  return toolbox;
}

module.exports = { run };

In conclusion, there are many great tools available for building NodeJS CLI tools, each with their own strengths and weaknesses. Choosing the right tool for your project will depend on your specific requirements and preferences.