Learning Some Node Basics

Some Notes on Node and NPM

Node.js

• An open-source, cross-platform JavaScript runtime environment
• Allows JavaScript to be used in server-side applications
• Built to handle many asynchronous activities

Node.js is a runtime environment

• It is a software framework that provides infrastructure and resources for executing programs
• It serves as an intermediary layer between the hardware and the software application

Node.js uses an event driven, non-blocking I/O model

• Event-driven: reacting to events as they occur
• Non-blocking: program doesn't halt while waiting for non-JavaScript operations
• I/O (Input/Output) model: interaction between CPU and external devices/resources
• Essentially, Node.js allows the program to handle multiple I/O tasks concurrently without waiting for one to complete

Node.js allows developers to write server-side applications using JavaScript

• JavaScript was originally for front-end only
• Promotes code reuse and consistency across the full-stack

Node.js is single-threaded but has an event loop to manage asynchronous operations

• Single-threaded: uses only one main execution thread to carry out tasks
• Event-loop: a continuous loop that runs throughout the lifetime of the application and handles certain events
• While Node.js only has one execution thread, the event-loop allows for it to handle multiple I/O tasks without blocking the main execution thread.

NPM

• The default package manager for Node
• Node packages help share modules between Node developers

Package Management

• Allows developers to install packages directly into their projects. These packages can be libraries, frameworks, tools, etc.
• Developers manage dependencies for their project in the package.json file, which lists all the dependencies for the project to run.

Script Execution

• npm also allows for the creation of custom scripts in the package.json file.
• These scripts can be run by using npm run <script name> or by clicking the play button next to the script definition in the package.json file

Some Application Help

Using Node

Make sure you have node installed. Run node -v to verify that it is installed correctly.

Now we can create a test script. I created a file called basic.js, but the only important part is the .js extension. In that file, you can write some simple JavaScript code, such as a console.log statement.

Next we can run that script by running node basic.js in the terminal.

Using NPM

Make sure you have npm installed. It should come bundled with Node.js, but you can run npm -v to verify that it is installed correctly.

Next we need to create a package.json file to manage the project's dependencies and metadata. You can run npm init in the terminal to create one. Follow the prompts to set it up.

We can then install packages using npm install. For example, I installed the Express.js framework by running npm install express. Doing this will also create a package-lock.json file. You don't need to worry about doing anything with that file.

We can access installed packages using require(). Check the basic.js file for an example of using the express package