Aadityasiva

Posted on Jan 30, 2021

Make and publish a NodeJS CLI in 10 minutes!!

#node #npm #javascript

In this post you will make a NodeJS command line calculator and publish it to NPM all in just 10 minutes. So without any further ado lets start

Step 1 - Setup

Name and create a project folder

  mkdir <insert project name>
  cd <insert project name>

Initialize NPM

  npm init -y

This command will create a package.json file this file will contain all the details of our package

Create a file called cli.js in the root of our project this is the file in which we will write code
Open the cli.js file and add this on the first line

  #!/usr/bin/env node

This line will let our code know where to find NodeJS command

Open the package.json file and at the very bottom add this line

  "bin": "cli.js"

This line will let NPM know which file contains the code to execute when called

Step 2 - Code

Open up the cli.js file and add the following code

let args = process.argv.slice(2);
console.log(eval(args[0]));

Now your cli.js file should look like this

#!/usr/bin/env node
let args = process.argv.slice(2);
console.log(eval(args[0]));

Now let me explain the code line by line

#!/usr/bin/env node This line will let our code know where to find NodeJS command
let args = process.argv.slice(2); this line will get the command line arguments given to the command line
console.log(eval(args[0])); Now this line will get the first argument and evaluate it and then print it out on the console.

Step 3 - Testing it out locally

First run

npm link

This will simulate a global install
Now open up your package.json and see the "name" value and run like this

(Your package name in the package.json) 1+1

Now after testing it out run

npm unlink

Step 4 - Publishing!

Now before publishing to NPM you project needs to have a git repository so for that run this

git init .
git add .
git commit -m "My awesome CLI is ready"

and after you have initialized a git repository you will need a NPM account for that sign up here after signing up run this

npm login

after you enter your credentials you will be logged in
and finally run

npm publish

Now your command line tool is ready! Congratulation 🎉

Finishing up

If you are interested in seeing the whole code check them out on my GitHub
https://github.com/aadityasivaS/node-calc-cli

and the package is also on NPM
https://www.npmjs.com/package/@aadityasiva/n-c-c

Spoiler: Yes I saved it for last it may or may not take more than 10 minutes. It took me 5 minutes to do all the steps

Bye 👋 and good day

Top comments (4)

Andrew Bridge • Jan 30 '21

Nice! I find making Node CLIs to be a good way of keeping things cross-platform friendly while still providing the flexibility of the command line.

For more complex projects, I use Commander.js which does a lot of the boilerplate stuff (like parsing arguments and flags) for you.

It allows you to write quite neat code like:

program
   .version('0.0.1')
   .option('-C, --chdir <path>', 'change the working directory')
   .option('-c, --config <path>', 'set config path. defaults to ./deploy.conf')
   .option('-T, --no-tests', 'ignore test hook')

 program
   .command('setup')
   .description('run remote setup commands')
   .action(function() {
     console.log('setup');
   });

 program
   .command('exec <cmd>')
   .description('run the given remote command')
   .action(function(cmd) {
     console.log('exec "%s"', cmd);
   });