Skill Module

Build CLI Apps in JavaScript & Node.js

4 branches·45 chapters·17 projects

Learn how to build, integrate, and safeguard scalable CLI tools, scripts, and apps with JavaScript, Node.js, npm, and Git.

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About this module

This module turns programming fundamentals into real tools.

You'll build up solid JavaScript instincts — including working with numbers, strings, collections, functions, regular expressions, errors, and basic object-orientation — then apply them in the Node.js runtime where programs interact with the file system, handle events, process streams, and respond instantly to user input.

You'll learn to structure CLI programs that behave like utilities: parse arguments, read and write files, transform data, and report errors clearly. The projects are designed to sharpen thinking about input/output, state, and edge cases, which is exactly what teams expect from junior developers.

You'll learn how to use npm for finding the right packages, managing dependencies cleanly, automating tasks with scripts, and even publishing your own modules. You'll also practice real version-control habits with Git and GitHub so your work is reviewable, reversible, and collaborative.

By the end, you will be able to design, build, version, and ship command-line tools that solve concrete problems, and you'll be fully prepared to step into the world of API development next.

What you'll learn

Here's a shortlist of the key points you'll master by the end of this module.

Understand the fundamentals of the JavaScript language
Work with data structures, conditional logic, loops, and functions to solve real problems
Apply core software design concepts and patterns
Build command line tools and scripts that automate work
Write responsive and asynchronous programs in Node.js
Use npm to install, manage, and publish packages
Track and rewind changes to your codebase with Git
Collaborate with other developers using branches, pull requests, and reviews

The curriculum

Here's an overview of the chapters composing this module, organized by sections.

The JavaScript Programming Language

20 chapters·20 weeks·12 projects

The JavaScript Language Syntax
Storing and Reusing Data With Variables in JavaScript
Controlling the Execution Flow With Conditional Statements in JavaScript
Combining Conditions in JavaScript
Working With Numbers in JavaScript I
Working With Strings in JavaScript I
Repeating Instructions With Loops in JavaScript
Reusing Code With Functions in JavaScript
Advanced Functions in JavaScript
Keyed Data Structures in JavaScript I
Working With Numbers in JavaScript II
Keyed Data Structures in JavaScript II
The JavaScript Object Notation
Indexed Data Structures in JavaScript I
Indexed Data Structures in JavaScript II
Working With Strings in JavaScript II
Matching Patterns With Regular Expressions in JavaScript
Object-Oriented Programming in JavaScript
Throwing & Handling Errors in JavaScript
Asynchronous Execution in Node.js

The Node.js Runtime Environment

9 chapters·8 weeks·5 projects

The Node.js Runtime Environment
The CommonJS Module System in Node.js
The ECMAScript Module System in Node.js
Manipulating Bytes in Node.js
Handling Asynchronous Events in Node.js
Writing CLI Programs in Node.js
Working With Files in Node.js
Working With Directories in Node.js
Handling Data Streams in Node.js

The Node Package Manager

8 chapters·2 weeks

The Node Package Manager
Searching for Packages on the npm Registry
Installing & Using npm Packages
Listing Installed npm Packages
Updating Installed npm Packages
Removing Installed npm Packages
Automating Common Tasks With npm Scripts
Publishing Packages on the npm Registry

The Git Version Control System

8 chapters·2 weeks

The Git Version Control System
The Git Workflow
Navigating & Comparing Commits in Git
Removing Uncommitted Files in Git
Restoring, Reverting & Resetting Changes in Git
Pushing & Pulling Commits in Git
Making & Reviewing Pull Requests in GitHub
The Gitflow Development Workflow

The projects you'll build

Employers don't just want impressive resumes anymore, they also want impressive proof. With Learn Backend, you'll build a GitHub repository that actually proves you know backend development.

Here's an overview of the practical, hands-on projects you'll build.

lb_imdb

In this project, you'll write a JavaScript script that recommends a movie title based on a genre and a decade.

lb_schedule

In this project, you'll write a JavaScript script that determines whether a business is open or closed based on the day of the week and the time of the day.

lb_diamond

In this project, you'll write a JavaScript script that prints a diamond-shaped pyramid of variable size.

lb_radix

In this project, you'll write a JavaScript function that converts a number from a base to another base.

lb_recursive

In this project, you'll write a recursive JavaScript function that uses the digits of a number to generate all the possible arithmetic expressions that are equal to another number.

lb_for_honor

In this project, you'll write a JavaScript script that simulates a turn-based PvP fight between two heroes.

lb_pathfinder

In this project, you'll write a JavaScript script that finds the shortest travel itinerary between two interconnected cities.

lb_tictactoe

In this project, you'll write a JavaScript script that simulates and outputs a game of Tic-Tac-Toe play-by-play.

lb_spellit

In this project, you'll write a JavaScript script that translates a number made of digits to human-readable text.

lb_vigenere

In this project, you'll write a JavaScript script that implements a polyalphabetic substitution cipher that encrypts plain text strings using another string as encryption key.

lb_markup

In this project, you'll write a JavaScript script that converts Markdown to HTML.

lb_blockchain

In this project, you'll write a JavaScript script that implements a simple blockchain that simulates the exchange of digital currency between users.

lb_cron

In this project, you'll write a JavaScript task scheduler script that periodically executes asynchronous functions at fixed intervals.

lb_bc

In this project, you'll write a Node.js command-line script that partially reimplements the `bc` utility.

lb_wc

In this project, you'll write a Node.js script that partially reimplements the `wc` utility.

lb_ls

In this project, you'll write a Node.js script that partially reimplements the `ls` utility.

lb_csv2json

In this project, you'll write a Node.js script that converts a CSV file to a JSON file using a Transform stream.

Who is this for?

Beginners who want to discover the fundamentals of software development
Software developers who want to transition to backend development with Node.js

Do I need prior knowledge?

To complete this module, you will need to be familiar with the following topics.

💻

CLI & Scripting with Bash

Beginner·34 chapters

Learn how to gain advanced control over the OS and automate complex routine tasks prone to manual errors with the CLI and Bash scripting.

Discover

Why learn from me?

Hi, I'm Razvan 👋 — A senior Node.js backend engineer, technical writer, online teacher, and founder of Learn Backend.

It's no secret: learning backend development on your own is extremely hard.

Before becoming a senior Node.js engineer with now over a decade of experience, I also failed at it for years... and probably for the same reasons you're struggling with it right now.

The internet is full of content, but very little direction. No one tells you what to learn first, what to ignore, or how it all fits together.

This is why I created Learn Backend: a roadmap that teaches the core principles first, gradually introduces hands-on skills, and shows how all the pieces logically fit together.

I wanted to give people like me, and maybe you, the best fighting chance to make it in the software industry as job-ready backend developers — without wasting the years or facing the same unnecessary hurdles I did.

So if you're tired of guessing what to learn next or overwhelmed by all the noise, Learn Backend was built for you.

What developers say about it

Our content isn't guesswork. It's continuously reviewed by professional web developers, and here's what some of them have to say...

This module covers the real foundations you expect from someone who says "I can code in Node". It perfectly aligns with what we ask juniors to do in actual tasks.

Gabriel F

Senior Backend Developer

I think the project list is the strongest part. These projects force the student to reason about I/O, state, and edge cases, which is the difference between "I watched a crash course" and "I can write a tool that solves a problem".

Jean-Baptiste M

Senior Frontend Developer

The way asynchronous behavior in Node.js is handled is accurate and presented in increasing complexity. It really teaches how Node behaves and why, which reduces a ton of confusion later when people start writing servers.

Corentin G

Senior Full-Stack Developer

Peek inside the module

Explore these full-length lessons to see exactly what you'll get and how you'll learn once inside.

Repeating Instructions With Loops in JavaScript

JavaScript·33 min read

In programming, loops are control structures that allow you to repeat the execution of a set of instructions until a certain condition is met...

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Writing CLI Programs in Node.js

Node.js·55 min read

Node.js is a great versatile tool that packages all the functionalities needed to write a variety of command-line interface programs, such as file management tools...

Read