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The components of node are: 1. "V8 engine", which is a JavaScript interpreter, which is responsible for parsing and executing JavaScript code; 2. "Local module", which integrates many high-performance open source libraries and uses "C /C" is written, which determines the strength of Node's functions from the bottom layer; 3. "Standard library".
The operating environment of this tutorial: windows7 system, nodejs version 12.19.0, DELL G3 computer.
Node.js was released in May 2009 and developed by Ryan Dahl. It is a JavaScript running environment based on the Chrome V8 engine. It uses an event-driven, non-blocking I/O model to allow JavaScript to run in A server-side development platform that makes JavaScript a scripting language on par with server-side languages such as PHP, Python, Perl, and Ruby.
Before Node.js, JavaScript could only run in the browser and be used as a web page script to add some special effects to the web page or communicate with the server. With Node.js, JavaScript can be separated from the browser and used directly on the computer like other programming languages. It can do whatever it wants without being restricted by the browser.
Composition of Node.js
Node.js is mainly composed of V8 engine, standard library and local modules, especially the number of local modules , determines the strength of Node.js functions 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 module and the runtime in the browser , and even said that 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.
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