[Custom CLI] Develop and Publish a Node.js CLI from Scratch

Before you use any frameworks, you should know the fundamentals of what makes Node CLI's tick. Here we explain everything you need to know to write a complete Node.js CLI from scratch, parse arguments, publish it to NPM for users, and set up yarn symlinks for optimal developer experience.

 

Create a mycli.js file, in the very first line, we will add this code

#!/usr/bin/env node

It tells the running env. The benenfits for that is in order to run mycli.s file:

// Before
node ./mycli.js

// After
./mycli.js

 

Pass the argv:

We also want to pass some information into file, in order to do some operations.

./mycli.js myapp --name=Answer1215

They way to get the information is using:

process.argv

If we log the value:

[ '/usr/local/bin/node',
  '/Users/zhentianwan/Documents/programming/cus-cli/mycli.js',
  'myapp',
  '--name=good' ]

The first two is always there, the other information you pass into the cli, it will be push to the array.

 

In order for easy testing cli, we can publish to npm, or just using:

yarn link --global