References

Frameworks

caporal.js - building commandline apps in node.js website, tutorial
commander.js - most-popular CLI framework in node.js website
vorpal - immersive CLI builder framework, good code structure
vantage - CLI + SSH + REPL for your live node app; built on top of vorpal
lodash - tutorial
node-config - node.js configuration library
Crypto-js - crypto library.
inquirer.js - a node.js library for creating interactive CLI
abbrev-js - provide abbreviation of terms for CLI tools
isomorphic-git - pure JS implementation of git for node and browsers

Documentation

JSDoc - home, tutorial tutorial on require module
UML diagrams - plantUML, online demo
module dependency diagrams using madge and graphviz

Node.js and JS resources

helpful Node.js articles
node.js and JS compatibility
node.js event loop

Testing

CLI Testing - use child process and streams modules along with mocha and chai. tutorial
Streams documenatation
unit testing CLI programs

Books to Read

Eloquent Javascript
ExploringJS - Speaking JavaScript, Exploring ES6, Exploring ES2016 and ES2017
Book list
superherojs - compilation of resources
Venkat Subramaniam - Test-Driving JavaScript Applications: Rapid, Confident, Maintainable Code