Day 1: Introduction to Node.js: Basics, Installation, Modules

Day 1: Introduction to Node.js: Basics, Installation, Modules

Section 1: Introduction to Node.js

Unit 1: What is Node.js?

  • Brief History of Node.js

Node.js was created by Ryan Dahl in 2009, who was looking to create real-time websites with push capability. Dahl was dissatisfied with the current web technology which, at that time, was primarily based on request/response stateless paradigm. Node.js was therefore born as a JavaScript runtime built on Chrome’s V8 JavaScript engine. It was developed to build scalable network applications.

  • Importance and Applications of Node.js

Node.js is essential in modern web development, especially in building highly scalable, data-intensive, real-time back-end services. It is used by many large companies such as Netflix, LinkedIn, Uber, and eBay. It is favored for its efficiency and speed, as it uses a non-blocking, event-driven I/O model. Node.js is also popular for the development of web servers, networking tools, and real-time web APIs.

  • Node.js Vs Browser JavaScript

While both run JavaScript, there are several differences between Node.js and Browser JavaScript. The most prominent distinction is the environment they run in. Browser JavaScript runs in a browser, while Node.js runs directly on a computer or server OS. This gives Node.js more power and capabilities, such as directly interacting with the file system, something which is restricted in Browser JavaScript for security reasons.

Unit 2: How Node.js Works?

  • Event-driven architecture

Node.js uses an event-driven architecture which means everything that happens in Node is the result of an event. This is advantageous for handling high-throughput scenarios. Server-side operations, such as network requests, file system operations, and database operations, can be performed asynchronously.

  • Single-threaded nature of Node.js

Node.js is single-threaded, meaning it services incoming requests on a single thread on a single core of the server’s CPU. While this may seem counter-intuitive for scalability, the key to Node’s efficiency is its non-blocking I/O model. Node delegates tasks such as file system read/write operations, network calls, and database operations to the system’s kernel, which is multi-threaded.

  • The Node.js Event Loop

The event loop is at the heart of Node.js. It is a control structure that manages an event queue and the execution of callbacks associated with these events. When Node.js starts, it initializes the event loop, processes the provided input script (which may make async API calls, schedule timers, or call process.nextTick()), and then begins processing the event loop.

The event loop enables Node.js to perform non-blocking I/O operations — despite the fact that JavaScript is single-threaded — by offloading operations to the system kernel whenever possible. Since most modern kernels are multi-threaded, they can handle multiple operations executing in the background. When one of these operations completes, the kernel informs Node.js so that the appropriate callback may be added to the poll queue to eventually be executed.

Section 2: Setting Up Node.js

Unit 3: Installing Node.js

  • Requirements for Node.js installation

Before you can install Node.js, you need to have a compatible operating system. Node.js is compatible with Windows, Linux, and macOS. It’s recommended that you have a modern operating system with the latest updates installed.

  • Step-by-step guide to install Node.js on different Operating Systems

Windows and macOS:

  1. Visit the official Node.js website at https://nodejs.org/.
  2. There, you’ll see download links for Windows and macOS. Click on the one that corresponds to your operating system. As of writing, two versions are typically available: LTS and Current. The LTS version is recommended for most users.
  3. Once the installer is downloaded, run it. Follow the prompts in the Node.js Setup Wizard to complete the installation.

Linux:

Different Linux distributions have different methods for installing Node.js. For most, you can use the package manager to install Node.js. Here’s how to do it on Ubuntu:

  1. First, update your package manager repository with the command sudo apt update.
  2. Then, install Node.js with the command sudo apt install nodejs.
  3. Node.js comes with npm, the package manager for Node.js. You can install it with the command sudo apt install npm.
  • Verifying the installation

To ensure Node.js is installed correctly, open a terminal (or command prompt on Windows), and type node -v. This should return the version number of the installed Node.js.

Unit 4: Setting up the Development Environment

  • Overview of IDEs and text editors for Node.js (Visual Studio Code, Sublime Text, Atom, etc.)

You can write Node.js code in any text editor, but Integrated Development Environments (IDEs) or advanced text editors provide additional features such as syntax highlighting, autocompletion, and debugging tools.

  1. Visual Studio Code (VS Code): This is a free, open-source editor developed by Microsoft. It’s highly customizable and has a wide range of extensions, including excellent support for Node.js development.
  2. Sublime Text: This is a lightweight, highly customizable text editor. It is known for its speed, ease of use, and strong community support.
  3. Atom: Developed by GitHub, Atom is a free, open-source text editor that’s customizable but comes with a lot of out-of-the-box functionality. It includes built-in package manager to add plugins, and supports Node.js development well.
  • Installation and configuration of chosen IDE

Installation of these IDEs is generally straightforward – visit their official websites, download the installer for your operating system, and follow the installation prompts.

Once installed, you can configure the IDE for Node.js development. For example, in VS Code, you might want to install extensions such as ESLint for linting JavaScript code, or the Node.js Extension Pack for a collection of extensions that will enhance Node.js development.

Remember to set up your IDE to match your personal development preferences and to make your coding as efficient and enjoyable as possible.

Section 3: Basics of Node.js

Unit 5: Your First Node.js Script

  • Creating and running a simple “Hello, World!” script
  1. Open your chosen text editor or IDE, create a new file, and save it as hello.js.
  2. In hello.js, type the following line of code:
console.log('Hello, World!');
  1. Save the file and run it from your terminal by navigating to the directory containing the file and executing the command node hello.js. You should see the output ‘Hello, World!’.
  • Understanding the process object in Node.js

The process object is a global object that can be accessed from anywhere. It provides information about, and control over, the current Node.js process.

The process object provides several useful properties and methods. For example, process.exit() can be used to end the process, process.cwd() returns the current working directory, and process.version gives the Node.js version.

Unit 6: Modules in Node.js

  • Understanding the concept of modules

Modules in Node.js are akin to libraries in other programming languages. They’re blocks of encapsulated code that can be reused across multiple programs. A module can include a library of functions, a single function, an object, or any valid JavaScript values.

  • Exploring built-in modules in Node.js

Node.js has several built-in modules that make it a powerful environment for developing server-side applications. Some commonly used built-in modules include:

  1. fs for file system operations.
  2. http for making HTTP requests and creating HTTP servers.
  3. path for working with file and directory paths.
  4. os for interacting with the operating system.
  • Importing and using modules

To use a module in Node.js, you need to import it using the require function. For instance, to use the fs module, you would write:

var fs = require('fs');

Once a module is required, you can use its methods. For example, to read a file using the fs module, you would do:

fs.readFile('test.txt', 'utf8', function(err, data){
    if (err) throw err;
    console.log(data);
});
  • Creating and exporting your own modules

You can also create your own modules in Node.js. Suppose you have a function to calculate the area of a circle that you want to reuse in different files. You could create a circle.js file:

function area(radius) {
    return Math.PI * radius * radius;
}

module.exports = area;

Then, in another file, you could import your circle module and use the area function:

var circleArea = require('./circle');

console.log(circleArea(5));  // prints the area of a circle with radius 5

Note that module.exports is used to define what a module should export. In this case, it’s exporting the area function.

Section 4: Practice and Assignments

Unit 7: Practice Exercise

Exercise 1: Writing Scripts

Create a simple script that outputs the current date and time in a human-readable format.

Exercise 2: Using Built-in Modules

Using the fs module, write a script that reads a text file and outputs the content to the console.

Exercise 3: Creating and Using Custom Modules

Create a custom module that exports a function for calculating the square of a number. Then, in a separate file, import this module and use the function.

Unit 8: Assignment

Your assignment is to create a simple command line application: A Basic Calculator. The calculator should be able to perform basic operations like addition, subtraction, multiplication, and division.

For example, running node calculator.js add 5 7 should print 12 to the console.

This assignment helps reinforce what you’ve learned about writing Node.js scripts and creating and using modules.

Unit 9: Resources for Further Learning

  • Node.js Documentation: The official Node.js documentation is a great resource for learning more about Node.js, including its built-in modules and API.
  • Node.js Guides: These guides provide a comprehensive set of materials about various topics in Node.js.
  • The Node Beginner Book: This online book is a great resource for people who are new to Node.js.
  • MDN Web Docs: MDN has a thorough tutorial that introduces server-side development with Node.js and Express.js.

Remember, the key to mastering Node.js (like any programming language or framework) is consistent practice and continual learning. Take on small projects, read documentation, solve problems, and don’t hesitate to look for help in the wide array of online coding communities if you get stuck.