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Make and publish a NodeJS CLI in 10 minutes!!

Aadityasiva
👋 I am Aadityasiva Sabarinathan a cross platform developer and a graphic designer. I develop for mobile, desktop, web and packages for other developers.
・2 min read

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>
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  • Initialize NPM
  npm init -y
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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
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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"
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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]));
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Now your cli.js file should look like this

#!/usr/bin/env node
let args = process.argv.slice(2);
console.log(eval(args[0]));
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Now let me explain the code line by line

  1. #!/usr/bin/env node This line will let our code know where to find NodeJS command
  2. let args = process.argv.slice(2); this line will get the command line arguments given to the command line
  3. 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
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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
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Now after testing it out run

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

npm publish
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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

Discussion (4)

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andrewbridge profile image
Andrew Bridge

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);
   });
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aadityasiva profile image
Aadityasiva Author • Edited

Thanks for sharing really appreciate it

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webdevjeet profile image
Jeet Mandaliya

This is awesome !

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aadityasiva profile image
Aadityasiva Author

Thanks