| Node.js | |
|---|---|
 | |
| Original author | Ryan Dahl |
| Developer | OpenJS Foundation |
| Initial release | May 27, 2009; 16 years ago (2009-05-27)[1] |
| Stable release | |
| Written in | JavaScript,C++,Python,C |
| Operating system | z/OS,Linux,macOS,Microsoft Windows,SmartOS,FreeBSD,OpenBSD,IBM AIX[3] |
| Type | Runtime environment |
| License | MIT License[4][5] |
| Website | nodejs |
| Repository | |
| Program execution |
|---|
| General concepts |
| Types of code |
| Compilation strategies |
| Notable runtimes |
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| Notable compilers & toolchains |
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Node.js is across-platform,open-sourceJavaScriptruntime environment that can run onWindows,Linux,Unix,macOS, and more. Node.js runs on theV8JavaScript engine, and executes JavaScript code outside aweb browser. According to the Stack Overflow Developer Survey, Node.js is one of the most commonly used web technologies.[6]
Node.js lets developers use JavaScript to writecommand line tools andserver-side scripting. The ability to run JavaScript code on the server is often used to generatedynamic web page content before the page is sent to the user's web browser. Consequently, Node.js represents a "JavaScript everywhere"paradigm,[7] unifyingweb-application development around a singleprogramming language, as opposed to using different languages for the server- versus client-side programming.
Node.js has anevent-driven architecture capable ofasynchronous I/O. These design choices aim to optimizethroughput andscalability in web applications with many input/output operations, as well as forreal-time Web applications (e.g.,real-time communication programs andbrowser games).[8]
The Node.jsdistributed development project was previously governed by the Node.js Foundation,[9] and has now merged with theJS Foundation to form theOpenJS Foundation. OpenJS Foundation is facilitated by theLinux Foundation's Collaborative Projects program.[10]
Node.js was initially written byRyan Dahl in 2009,[11] about 13 years after the introduction of the first server-side JavaScript environment,Netscape's LiveWire Pro Web.[12] The initial release supported only Linux and Mac OS X. Its development and maintenance was led by Dahl and later sponsored byJoyent.[13]
Dahl criticized the limited capability ofApache HTTP Server to handle many (10,000+) concurrent connections, as well as the dominant programming paradigm of sequential programming, in which applications could block entire processes or cause the creation of multiple execution stacks for simultaneous connections.[citation needed]
Dahl demonstrated the project at the inaugural European JSConf on November 8, 2009.[14][15][16] Node.js combinedGoogle'sV8 JavaScript engine, anevent loop, and a low-levelI/OAPI.[17]
In January 2010, apackage manager was introduced for the Node.js environment callednpm.[18] The package manager allows programmers to publish and share Node.jspackages, along with the accompanying source code, and is designed to simplify the installation, update and uninstallation of packages.[17]
In June 2011, Microsoft and Joyent implemented a nativeWindows version of Node.js.[19] The first Node.js build supporting Windows was released in July 2011.
In January 2012, Dahl yielded management of the project to npm creator Isaac Schlueter.[20] In January 2014, Schlueter announced that Timothy J. Fontaine would lead the project.[21]
In December 2014, Fedor Indutny created io.js, afork of Node.js created because of dissatisfaction with Joyent's governance as anopen-governance alternative with a separate technical committee. The goal was to enable a structure that would be more receptive to community input, including the updating of io.js with the latest Google V8 JavaScript engine releases, diverging from Node.js's approach at that time.[22]
The Node.js Foundation, formed to reconcile Node.js and io.js under a unified banner, was announced in February 2015.[23] The merger was realized in September 2015 with Node.js v0.12 and io.js v3.3 combining into Node v4.0.[24] This merge brought V8ES6 features into Node.js and started a long-term support release cycle.[25] By 2016, the io.js website recommended returning to Node.js and announced no further io.js releases, effectively ending the fork and solidifying the merger's success.[26]
In 2019, the JS Foundation and Node.js Foundation merged to form theOpenJS Foundation.
The Node.js logo features a green hexagon with overlapping bands to represent the cross-platform nature of the runtime.[27] The Rocket Turtle was chosen as the official Node.js mascot in February 2024 following a design contest.[28]
Node.js allows the creation ofweb servers and networking tools usingJavaScript and a collection of "modules" that handle various core functionalities.[14][17][29][30][31][excessive citations] Modules are provided forfile system I/O, networking (DNS,HTTP,TCP,TLS/SSL orUDP),binary data (buffers),cryptography functions,data streams and other core functions.[17][30][32] Node.js's modules use an API designed to reduce the complexity of writing server applications.[17][30]
Since version 22.6.0, Node.js natively supports bothJavaScript andTypeScript, allowing TypeScript files to be executed without a separate compilation step.[33] The TypeScript support was contributed by Node.js TSC member Marco Ippolito. In addition, manycompile-to-JS languages are available,[34] allowing Node.js applications to also be written inCoffeeScript,[35]Dart,ClojureScript, and others.
Node.js is primarily used to build network programs such as web servers.[29] The most significant difference between Node.js andPHP is that most functions in PHPblock until completion (commands execute only after previous commands finish), while Node.js functions arenon-blocking (commands executeconcurrently and usecallbacks to signal completion or failure).[29]
Node.js is officially supported byLinux,macOS andMicrosoft Windows 8.1 and Server 2012 (and later),[3] with Tier 2 support forSmartOS andIBM AIX and experimental support forFreeBSD.OpenBSD also works, and LTS versions are available forIBM i (AS/400).[36] The source code may also be built on similar operating systems that are not officially supported, such asNonStop OS[37] andUnix servers.
Node.js enables development of fast web servers in JavaScript usingevent-driven programming.[17] Developers can create scalable servers without usingthreading by using a simplified model that usescallbacks to signal the completion of a task.[17][page needed] Node.js connects the ease of a scripting language (JavaScript) with the power of Unix network programming.[17]
Node.js was built on top of Google's V8 JavaScript engine since it was open-sourced under theBSD license, and it contains comprehensive support for fundamental protocols such asHTTP,DNS andTCP.[14] JavaScript's existing popularity made Node.js accessible to theweb-development community.[14]
There are thousands of open-source libraries for Node.js, most of which are hosted on the npm website. Multiple developer conferences and events are held that support the Node.js community, including NodeConf, Node Interactive, and Node Summit, as well as a number of regional events.
The open-source community has developedweb frameworks to accelerate the development of applications. Such frameworks includeExpress.js,Socket.IO,Sails.js,Next.js andMeteor.[17][38] Various packages have also been created for interfacing with other languages or runtime environments such asMicrosoft .NET.[39]
Modern desktopIDEs provide editing and debugging features specifically for Node.js applications. Such IDEs includeAtom,Brackets,JetBrainsWebStorm,[40][41]Microsoft Visual Studio (with Node.js Tools for Visual Studio,[42] orTypeScript with Node definitions[43][44][45][46]),NetBeans,[47] Nodeclipse Enide Studio[48] (Eclipse-based) andVisual Studio Code.[49][50] Someonline IDEs also support Node.js, such asCodeanywhere,Eclipse Che,Cloud9 IDE and the visual flow editor inNode-RED.
Node.js is supported across a number of cloud-hosting platforms such asJelastic,Google Cloud Platform,AWS Elastic Beanstalk,Azure Web Apps andJoyent.
New major releases of Node.js are cut from theGitHub main branch every six months. Even-numbered versions are cut in April and odd-numbered versions are cut in October. When a new odd version is released, the previous even version undergoes transition toLong Term Support (LTS), which gives that version 12 months of active support from the date it is designated LTS. After these 12 months expire, an LTS release receives an additional 18 months of maintenance support. An active version receives non-breaking backports of changes a few weeks after they land in the current release. A maintenance release receives only critical fixes and documentation updates.[51] The LTS Working Group manages strategy and policy in collaboration with the Technical Steering Committee of the Node.js Foundation.
| Release[52] | Status | Code name | Release date | Maintenance end |
|---|---|---|---|---|
| Unsupported: 0.10.x | Unsupported: End-of-Life | 2013-03-11 | 2016-10-31 | |
| Unsupported: 0.12.x | Unsupported: End-of-Life | 2015-02-06 | 2016-12-31 | |
| Unsupported: 4.x | Unsupported: End-of-Life | Argon[51] | 2015-09-08 | 2018-04-30 |
| Unsupported: 5.x | Unsupported: End-of-Life | 2015-10-29 | 2016-06-30 | |
| Unsupported: 6.x | Unsupported: End-of-Life | Boron[51] | 2016-04-26 | 2019-04-30 |
| Unsupported: 7.x | Unsupported: End-of-Life | 2016-10-25 | 2017-06-30 | |
| Unsupported: 8.x | Unsupported: End-of-Life | Carbon[51] | 2017-05-30 | 2019-12-31 |
| Unsupported: 9.x | Unsupported: End-of-Life | 2017-10-01 | 2018-06-30 | |
| Unsupported: 10.x | Unsupported: End-of-Life | Dubnium[51] | 2018-04-24 | 2021-04-30 |
| Unsupported: 11.x | Unsupported: End-of-Life | 2018-10-23 | 2019-06-01 | |
| Unsupported: 12.x | Unsupported: End-of-Life | Erbium[51] | 2019-04-23 | 2022-04-30 |
| Unsupported: 13.x | Unsupported: End-of-Life | 2019-10-22 | 2020-06-01 | |
| Unsupported: 14.x | Unsupported: End-of-Life | Fermium[51] | 2020-04-21 | 2023-04-30 |
| Unsupported: 15.x | Unsupported: End-of-Life | 2020-10-20 | 2021-06-01 | |
| Unsupported: 16.x | Unsupported: End-of-Life | Gallium[51] | 2021-04-20 | 2023-09-11[53] |
| Unsupported: 17.x | Unsupported: End-of-Life | 2021-10-19 | 2022-06-01 | |
| Unsupported: 18.x | Unsupported: End-of-Life | Hydrogen[51] | 2022-04-19 | 2025-04-30 |
| Unsupported: 19.x | Unsupported: End-of-Life | 2022-10-18 | 2023-06-01 | |
| Supported: 20.x | Supported: Maintenance LTS | Iron[54] | 2023-04-18 | 2026-04-30 |
| Unsupported: 21.x | Unsupported: End-of-Life | [51] | 2023-10-17 | 2024-06-01 |
| Supported: 22.x | Supported: Maintenance LTS | Jod[54][51] | 2024-04-24 | 2027-04-30 |
| Unsupported: 23.x | Unsupported: End-of-Life | [51] | 2024-10-15 | 2025-06-01 |
| Latest version:24.x | Latest version:Active LTS | Krypton[54] | 2025-04-22 | 2028-04-30 |
| Preview version: 25.x | Preview version: Current | 2025-10-15[55] | 2026-06-01 | |
| Future version: 26.x | Future version: Planned | Lithium[54] | 2026 | 2029 |
| Future version: 28.x | Future version: Planned | Magnesium[54] | 2027 | 2030 |
| Future version: 30.x | Future version: Planned | Neon[54] | 2028 | 2031 |
| Future version: 32.x | Future version: Planned | Oxygen[54] | 2029 | 2032 |
| Future version: 34.x | Future version: Planned | Platinum[54] | 2030 | 2033 |
Legend: Unsupported Supported Latest version Preview version Future version | ||||
Node.js is a JavaScript runtime environment that processes incoming requests in a loop, called theevent loop.
Node.js useslibuv under the hood to handle asynchronous events. Libuv is an abstraction layer for network and file system functionality on both Windows andPOSIX-based systems such as Linux,macOS, OSS onNonStop, and Unix. Node.js relies on nghttp2 for HTTP support. As of version 20, Node.js uses the ada library which provides up-to-dateWHATWGURL compliance. As of version 19.5, Node.js uses the simdutf library for fast Unicode validation and transcoding. As of version 21.3, Node.js uses the simdjson library for fast JSON parsing.
Node.js operates on asingle-threadevent loop, usingnon-blocking I/O calls, allowing it to support tens of thousands of concurrent connections without incurring the cost of threadcontext switching.[56] The design of sharing a single thread among all the requests that use theobserver pattern is intended for building highly concurrent applications, where any function performing I/O must use acallback. To accommodate the single-threaded event loop, Node.js uses thelibuv library—which, in turn, uses a fixed-sized thread pool that handles some of the non-blocking asynchronous I/O operations.[8]
A thread pool handles the execution of parallel tasks in Node.js. The main thread function call posts tasks to the shared task queue, which threads in the thread pool pull and execute. Inherently non-blocking system functions such as networking translate to kernel-side non-blocking sockets, while inherently blocking system functions such as file I/O run in a blocking way on their own threads. When a thread in the thread pool completes a task, it informs the main thread of this, which in turn, wakes up and executes the registered callback.
A downside of this single-threaded approach is that Node.js does not allowvertical scaling by increasing the number ofCPU cores of the machine it is running on without using an additional module, such as cluster,[57] StrongLoop Process Manager,[58] or pm2.[59] However, developers can increase the default number of threads in the libuv thread pool. The serveroperating system (OS) is likely to distribute these threads across multiple cores.[60] Another problem is that long-lasting computations and other CPU-bound tasks freeze the entire event-loop until completion.[citation needed]
V8 is the JavaScript execution engine which was initially built forGoogle Chrome. It was then open-sourced by Google in 2008. Written inC++, V8 compiles JavaScript source code to native machine codeat runtime.[8] As of 2016, it also includes Ignition, abytecode interpreter.
npm is the pre-installed package manager for the Node.js server platform. It installs Node.js programs from the npm registry, organizing the installation and management of third-party Node.js programs.
Node.js registers with the operating system so the OS notifies it ofasynchronous I/O events such as new connections. Within the Node.js runtime, events trigger callbacks and each connection is handled as a smallheap allocation. Traditionally, relatively heavyweight OS processes or threads handled each connection. Node.js uses an event loop for concurrent I/O, instead of processes or threads.[61] In contrast to other event-driven servers,[which?] Node.js's event loop does not need to be called explicitly. Instead, callbacks are defined, and the server automatically enters the event loop at the end of the callback definition. Node.js exits the event loop when there are no further callbacks to be performed.
Node.js supportsWebAssembly and as of Node 14 has experimental support ofWASI, the WebAssembly System Interface.
Node.js provides a way to create "add-ons" via aC-based API called N-API, which can be used to produce loadable (importable).node modules from source code written in C/C++.[62] The modules can be directly loaded into memory and executed from within JS environment as simple CommonJS modules. The implementation of the N-API relies on internal C/C++ Node.js and V8 objects requiring usersto import (#include) Node.js specificheaders into their native source code.[62]
As the Node.js API is subject to breaking changes at a binary level, modules have to be built and shipped against specific Node.js versions to work properly. To address the issue, third parties have introduced open-sourced С/С++ wrappers on top of the API that partially alleviate the problem. They simplify interfaces, but as a side effect they may also introduce complexity which maintainers have to deal with. Even though the core functionality of Node.js resides in a JavaScript built-in library, modules written in C++ can be used to enhance capabilities and to improve performance of applications.
In order to produce such modules one needs to have an appropriate C++ compiler and necessary headers (the latter are typically shipped with Node.js itself), e.g.,gcc,clang orMSVC++.
The N-API is similar toJava Native Interface.
In 2015, various branches of the greater Node.js community began working under the vendor-neutral Node.js Foundation. The stated purpose of the organization "is to enable widespread adoption and help accelerate development of Node.js and other related modules through an open governance model that encourages participation, technical contribution, and a framework for long-term stewardship by an ecosystem invested in Node.js' success."[63]
The Node.js Foundation Technical Steering Committee (TSC) is the technical governing body of the Node.js Foundation. The TSC is responsible for the core Node.js repo as well as dependent and adjacent projects. Generally the TSC delegates the administration of these projects to working groups or committees.[64] The LTS group that manages long term supported releases is one such group. Other current groups include Website, Streams, Build, Diagnostics, i18n, Evangelism, Docker, Addon API, Benchmarking, Post-mortem, Intl, Documentation, and Testing.[65]
In August 2017, a third of the TSC members resigned due to a dispute related to the project's code of conduct.[66]
| Username | Full Name |
|---|---|
| aduh95 | Antoine du Hamel |
| anonrig | Yagiz Nizipli |
| benjamingr | Benjamin Gruenbaum |
| BridgeAR | Ruben Bridgewater |
| gireeshpunathil | Gireesh Punathil |
| jasnell | James M Snell |
| joyeecheung | Joyee Cheung |
| legendecas | Chengzhong Wu |
| marco-ippolito | Marco Ippolito |
| mcollina | Matteo Collina |
| mhdawson | Michael Dawson |
| RafaelGSS | Rafael Gonzaga |
| richardlau | Richard Lau |
| ronag | Robert Nagy |
| ruyadorno | Ruy Adorno |
| ShogunPanda | Paolo Insogna |
| targos | Michaël Zasso |
| tniessen | Tobias Nießen |
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