Bonus: Node.js Glossary

# Node.js Glossary

Welcome to the Node.js Glossary. Backend development comes with a lot of new vocabulary. Use this page as a quick reference guide whenever you encounter a term you don't fully understand.

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A #

• API (Application Programming Interface): A set of rules that allows one piece of software application to talk to another. In web development, it usually refers to a backend server that serves data (JSON) to frontend applications.

• Asynchronous: A programming paradigm where tasks are executed in the background, allowing the main program to continue running without waiting for the task to finish. Crucial in Node.js for handling I/O operations.

B #

• Bcrypt: A popular cryptographic hashing function used to securely store passwords. It intentionally runs slowly to prevent brute-force attacks.

• BSON (Binary JSON): The data format MongoDB uses to store documents. It extends JSON to support more data types (like Dates and ObjectIds).

• Buffer: A temporary memory space in Node.js used to store raw binary data streams (like chunks of an incoming file upload) before they are fully processed.

C #

• Callback: A function passed into another function as an argument, which is then executed after some operation has been completed.

• CORS (Cross-Origin Resource Sharing): A security feature in browsers that restricts web pages from making requests to a different domain than the one that served the web page. Express uses the cors package to bypass this when necessary.

• CRUD: An acronym for the four basic operations of persistent storage: Create, Read, Update, Delete.

D #

• Deployment: The process of moving your application from your local development environment (your laptop) to a live production server accessible to the public.

• Document: The basic unit of data in MongoDB (equivalent to a row in SQL). It is a JSON-like object.

• Dotenv (.env): A module that loads environment variables from a .env file into process.env, keeping sensitive keys out of the source code.

E #

• EJS (Embedded JavaScript): A templating engine for Node.js that allows you to generate HTML markup with plain JavaScript injected into it.

• Environment Variable: A dynamic-named value that can affect the way running processes will behave on a computer, typically used to store database URIs, API keys, and port numbers.

• Event Loop: The mechanism that allows Node.js to perform non-blocking I/O operations despite being single-threaded, by offloading operations to the system kernel whenever possible.

• Express.js: A fast, unopinionated, minimalist web framework for Node.js that simplifies the process of building servers and APIs.

G #

• Global Error Handler: A special Express middleware function with four arguments (err, req, res, next) placed at the bottom of the app to catch and format all server errors.

H #

• Hashing: A one-way mathematical process that converts data (like a password) into a scrambled string of fixed length. It cannot be reversed.

• HTTP Methods: Verbs indicating the desired action to be performed for a given resource (e.g., GET, POST, PUT, DELETE).

J #

• JSON (JavaScript Object Notation): A lightweight, text-based data interchange format that is easy for humans to read and machines to parse.

• JWT (JSON Web Token): A secure, URL-safe string representing claims to be transferred between two parties. Used primarily for user authentication and stateless sessions.

M #

• Middleware: Functions in Express that have access to the request object (req), response object (res), and the next function. They execute in the middle of the request-response cycle.

• Module: A reusable block of code whose existence does not accidentally impact other code. Node.js uses require() to import modules.

• MongoDB: A popular NoSQL, document-oriented database system that stores data in flexible, JSON-like formats.

• Mongoose: An Object Data Modeling (ODM) library for MongoDB and Node.js that provides schema validation, model compilation, and query building.

• Multer: A node.js middleware for handling multipart/form-data, primarily used for uploading files.

N #

• Node.js: An open-source, cross-platform, backend JavaScript runtime environment that executes JavaScript code outside a web browser, built on Chrome's V8 engine.

• NoSQL: A class of database management systems that do not use the traditional relational (table-based) structure of SQL.

• NPM (Node Package Manager): The default package manager for Node.js, providing access to hundreds of thousands of reusable code libraries.

• Nodemon: A utility tool that monitors for any changes in your source code and automatically restarts your server.

P #

• Package.json: A file present in the root of every Node project that holds metadata relevant to the project, including scripts and dependencies.

• Params (Route Parameters): Named URL segments used to capture values specified at their position in the URL (e.g., /users/:id).

• Payload: The actual data pack being transmitted over a network. In JWTs, the payload usually contains the user's ID.

• Promise: An object representing the eventual completion (or failure) of an asynchronous operation and its resulting value. Used heavily with async/await.

Q #

• Query String: The part of a URL containing data that does not fit conveniently into a hierarchical path structure. Typically comes after a ? (e.g., /search?keyword=node).

R #

• REST (Representational State Transfer): An architectural style for designing networked applications relying on a stateless, client-server protocol, using standard HTTP methods.

• Route: A section of Express code that handles requests to a specific URL path and HTTP method.

S #

• Salt: Random data added to a password before it is hashed by algorithms like Bcrypt to defend against dictionary attacks and rainbow tables.

• Schema: A blueprint or set of rules defining the structure of data. In Mongoose, it defines the properties and validations for a MongoDB document.

• Stateless: A protocol (like HTTP) where the server does not retain any memory of past requests from the client. Every request must contain all necessary information (like a JWT) to be understood.

• Synchronous: A programming paradigm where operations execute one at a time, strictly in order. If an operation is slow, it blocks the entire program from continuing.

V #

• V8 Engine: Google's open-source high-performance JavaScript engine, written in C++, which powers Google Chrome and Node.js.