What is the engine of node.js?

The engine of node.js is "Chrome V8". Node.js is mainly composed of the Chrome V8 engine, standard library and local modules; among them, the V8 engine is responsible for parsing and executing JavaScript code. It directly compiles JS code into native machine code and uses a caching mechanism to improve performance.

The operating environment of this tutorial: windows7 system, nodejs version 12.19.0, DELL G3 computer.

What is nodejs?

Node.js is a JavaScript runtime environment based on the Chrome V8 engine.

Node.js uses an event-driven, non-blocking I/O model, making it lightweight and efficient.

Simply put, Node.js is JavaScript running on the server side, and JavaScript is used for programming on the server side.

Node.js is a development platform that allows JavaScript to run on the server side. It extends the reach of JavaScript to the server side and can be on an equal footing with PHP, JSP, Python, and Ruby.

Node.js is not an independent language. Unlike PHP, JSP, Python, Perl, and Ruby, which are both languages ​​and platforms, Node.js uses JavaScript for programming and runs on a JavaScript engine ( V8).

Nodejs development consists of using a large number of third-party packages provided by the npm development community plus the basic ECMAScript scripting language and a series of programming interfaces provided by the node platform for programming.

Composition of Node.js

Node.js runtime is mainly composed of V8 engine, standard library and local modules, especially local modules The amount of Node.js determines the strength of Node.js functionality from the bottom level.

1) V8 engine

The V8 engine is the JavaScript interpreter, which is responsible for parsing and executing JavaScript code.

The V8 engine draws on many technologies from the Java virtual machine and C compiler. It compiles JavaScript code directly into native machine code, and uses a caching mechanism to improve performance, which makes JavaScript run at a speed comparable to binary program.

2) Local module

Node.js integrates many high-performance open source libraries, which are implemented in C/C language, such as:

Module	Description
libuv	A cross-platform, event-driven asynchronous I/O library . But libuv is not limited to I/O, it also provides process management, thread pool, signal processing, timer and other functions. Everything in Linux is a file. I/O here includes not only file reading and writing, but also database reading and writing, network communication (socket), etc.
nmp	Node.js package manager, you can download packages, install packages, uninstall packages, update packages, upload packages, etc.
http_parser	A lightweight HTTP parser written in C language to support web application development.
zlib	Industrial-grade data compression/decompression module, Nodejs uses zlib to create synchronous, asynchronous or streaming compression/decompression interfaces.
OpenSSL	This module provides many of the rigorously tested encryption/decryption features that the modern web relies on for security, such as the SSL protocol and the https protocol.
c-ares	Asynchronous DNS query and resolution library.

Node.js runs JavaScript code directly on the computer and gives JavaScript powerful capabilities, so there are many big differences between its local modules and the runtime in the browser, and there is almost no connection. Node.js almost completely abandoned the browser and built a new JavaScript runtime from scratch.

3) Standard library

Local modules are written in C/C, and Node.js is for JavaScript developers, so the C/C interface of the local module must be encapsulated , provide a set of elegant JavaScript interfaces to developers, and maintain the consistency of the interface on different platforms (operating systems).

This set of JavaScript interfaces is the Node.js standard library. Whether the standard library is elegant and powerful determines the ease of use of Node.js and directly affects the market performance of Node.js.

Summary

The V8 engine and many local modules are ready-made. Others have already built the wheel. The main job of Node.js is to choose the appropriate module and integrate it. They are integrated together and the JavaScript interface is written.

Of course, not all local modules can be found suitable. Node.js has also written several modules of its own, the typical representative is Libuv. Libuv is the core and most basic module of Node.js. Node.js is completely built based on Libuv.

You may have heard that Node.js adopts an event-based, single-threaded asynchronous I/O architecture. This is the biggest feature of Node.js and the biggest difference between it and other scripting languages. Node. This ability of js is achieved by relying on Libuv.

Libuv is so powerful that the official decided to separate it from Node.js, release it as a separate network library, and make it open source and free. Now Libuv has become very popular, and is known as the "three major C/C network libraries" together with the traditional Libevent and libev libraries.

Node.js is famous mainly because it uses the V8 engine and the Libuv library: the V8 engine ensures that Node.js runs efficiently, and the Libuv library provides asynchronous I/O based on the event loop. ability.

Summary

Node.js is a JavaScript runtime, which allows JavaScript to be separated from the browser environment and can be run directly on the computer. Greatly expands the uses of JavaScript. We should treat JavaScript on the same level as other programming languages ​​such as Python, Java, and Ruby, and no longer treat it as a "gadget."

Finally, let’s summarize the history of JavaScript and Node.js:

• The Netscape browser derived JavaScript scripts, giving web page programming capabilities;

• The Chrome browser derives the V8 engine, which improves JavaScript performance;

• The V8 engine builds Node.js and expands JavaScript programming capabilities;

• Node.js derives the Libuv library, adding an excellent tool to network development.

For more node-related knowledge, please visit: nodejs tutorial!

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