Node Introduction

Node.js is an open-source, cross-platform JavaScript runtime environment that allows developers to run JavaScript code on the server side. Node.js was first released in 2009 by Ryan Dahl and is designed to build efficient and scalable network applications. Its core is based on Google's V8 JavaScript engine, which allows JavaScript to be executed not only in the browser but also on the server side.

A notable feature of Node.js is its non-blocking I/O model. This model enables Node.js to handle a large number of concurrent requests without blocking execution, greatly improving the performance and responsiveness of the application. Compared with traditional multi-threaded servers, Node.js uses a single-threaded event loop to handle concurrent requests, which can more efficiently utilize system resources. This design makes Node.js very suitable for building real-time applications such as online chat, games, and streaming services.

Node.js provides a rich set of built-in modules and a powerful package management tool npm (Node Package Manager), which is one of the world's largest open source library ecosystems. Developers can easily install, manage and share JavaScript libraries through npm, thereby accelerating the development process.

The Node.js ecosystem supports a variety of frameworks and libraries, such as Express.js, Koa.js, and Nest.js, which simplify the process of developing RESTful APIs and web applications. The flexibility and extensibility of Node.js make it suitable for a variety of application scenarios, including web servers, microservices, command-line tools, and IoT applications.

Because Node.js uses JavaScript as the main programming language, front-end developers can use the same language for full-stack development, which reduces the complexity of the technology stack and promotes collaboration between the front and back ends.

In general, Node.js is a powerful server-side JavaScript runtime environment that greatly improves developer productivity and application performance through a non-blocking I/O model and a rich ecosystem. With the increasing complexity of Internet applications and the increase in real-time requirements, Node.js is becoming an important choice for modern network development.