name : maintaining-dependencies.md # Maintaining Dependencies Node.js depends on additional components beyond the Node.js code itself. These dependencies provide both native and JavaScript code and are built together with the code under the `src` and `lib` directories to create the Node.js binaries. All dependencies are located within the `deps` directory. This a list of all the dependencies: * [acorn][] * [ada][] * [base64][] * [brotli][] * [c-ares 1.20.1][] * [cjs-module-lexer][] * [corepack][] * [googletest 2dd1c13][] * [histogram][] * [icu-small][] * [llhttp][] * [minimatch][] * [nghttp2][] * [ngtcp2][] * [npm][] * [openssl][] * [postject][] * [simdutf 4.0.4][] * [undici 5.26.4][] * [uv][] * [uvwasi 0.0.19][] * [V8][] * [zlib][] Any code which meets one or more of these conditions should be managed as a dependency: * originates in an upstream project and is maintained in that upstream project. * is not built from the `preferred form of the work for making modifications to it` (see [GNU GPL v2, section 3.](https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html) when `make node` is run. A good example is WASM code generated from C (the preferred form). Typically generation is only supported on a subset of platforms, needs additional tools, and is pre-built outside of the `make node` step and then committed as a WASM binary in the directory for the dependency under the `deps` directory. By default all dependencies are bundled into the Node.js binary, however, `configure` options should be available to use an externalized version at runtime when: * the dependency provides native code and is available as a shared library in one or more of the common Node.js distributions. * the dependency provides JavaScript and is not built from the `preferred form of the work for making modifications to it` when `make node` is run. Many distributions use externalized dependencies for one or more of these reasons: 1. They have a requirement to build everything that they ship from the `preferred form of the work for making modifications to it`. This means that they need to replace any pre-built components (for example WASM binaries) with an equivalent that they have built. 2. They manage the dependency separately as it is used by more applications than just Node.js. Linking against a shared library allows them to manage updates and CVE fixes against the library instead of having to patch all of the individual applications. 3. They have a system wide configuration for the dependency that all applications should respect. ## Supporting externalized dependencies with native code Support for externalized dependencies with native code for which a shared library is available can added by: * adding options to `configure.py`. These are added to the shared\_optgroup and include an options to: * enable use of a shared library * set the name of the shared library * set the path to the directory with the includes for the shared library * set the path to where to find the shared library at runtime * add a call to configure\_library() to `configure.py` for the library at the end of list of existing configure\_library() calls. If there are additional libraries that are required it is possible to list more than one with the `pkgname` option. * in `node.gypi` guard the build for the dependency with `node_shared_depname` so that it is only built if the dependency is being bundled into Node.js itself. For example: ```text [ 'node_shared_brotli=="false"', { 'dependencies': [ 'deps/brotli/brotli.gyp:brotli' ], }], ``` ## Supporting externalizable dependencies with JavaScript code Support for an externalizable dependency with JavaScript code can be added by: * adding an entry to the `sharable_builtins` map in `configure.py`. The path should correspond to the file within the deps directory that is normally bundled into Node.js. For example `deps/cjs-module-lexer/lexer.js`. This will add a new option for building with that dependency externalized. After adding the entry you can see the new option by running `./configure --help`. * adding a call to `AddExternalizedBuiltin` to the constructor for BuiltinLoader in `src/node_builtins.cc` for the dependency using the `NODE_SHARED_BUILTLIN` #define generated for the dependency. After running `./configure` with the new option you can find the #define in `config.gypi`. You can cut and paste one of the existing entries and then update to match the import name for the dependency and the #define generated. ## Supporting non-externalized dependencies with JavaScript code If the dependency consists of JavaScript in the `preferred form of the work for making modifications to it`, it can be added as a non-externalizable dependency. In this case simply add the path to the JavaScript file in the `deps_files` list in the `node.gyp` file. ## Updating dependencies Most dependencies are automatically updated by [dependency-update-action][] that runs weekly. However, it is possible to manually update a dependency by running the corresponding script in `tools/update-deps`. [OpenSSL][] has its own update action: [update-openssl-action][]. [npm-cli-bot](https://github.com/npm/cli/blob/latest/.github/workflows/create-node-pr.yml) takes care of [npm][] update, it is maintained by the npm team. ## Dependency list ### acorn The [acorn](https://github.com/acornjs/acorn) dependency is a JavaScript parser. [acorn-walk](https://github.com/acornjs/acorn/tree/master/acorn-walk) is an abstract syntax tree walker for the ESTree format. ### ada The [ada](https://github.com/ada-url/ada) dependency is a fast and spec-compliant URL parser written in C++. ### base64 The [base64](https://github.com/aklomp/base64) dependency is a base64 stream encoding/decoding library in C99 with SIMD and OpenMP acceleration. It also contains wrapper functions to encode/decode simple length-delimited strings. ### brotli The [brotli](https://github.com/google/brotli) dependency is used for the homonym generic-purpose lossless compression algorithm. ### c-ares 1.20.1 The [c-ares](https://github.com/c-ares/c-ares) is a C library for asynchronous DNS requests. ### cjs-module-lexer The [cjs-module-lexer](https://github.com/nodejs/node/tree/HEAD/deps/cjs-module-lexer) dependency is used within the Node.js ESM implementation to detect the named exports of a CommonJS module. See [maintaining-cjs-module-lexer][] for more information. ## corepack The [corepack](https://github.com/nodejs/corepack) dependency is a zero-runtime-dependency Node.js script that acts as a bridge between Node.js projects and the package managers they are intended to be used with during development. In practical terms, Corepack will let you use Yarn and pnpm without having to install them - just like what currently happens with npm, which is shipped by Node.js by default. ### googletest 2dd1c13 The [googletest](https://github.com/google/googletest) dependency is Google’s C++ testing and mocking framework. ### histogram The [histogram](https://github.com/HdrHistogram/HdrHistogram_c) dependency is a C port of High Dynamic Range (HDR) Histogram. ### icu-small The [icu](http://site.icu-project.org) is widely used set of C/C++ and Java libraries providing Unicode and Globalization support for software applications. See [maintaining-icu][] for more informations. ### llhttp The [llhttp](https://github.com/nodejs/llhttp) dependency is the http parser used by Node.js. See [maintaining-http][] for more informations. ### minimatch The [minimatch](https://github.com/isaacs/minimatch) dependency is a minimal matching utility. ### nghttp2 The [nghttp2](https://github.com/nghttp2/nghttp2) dependency is a C library implementing HTTP/2 protocol. See [maintaining-http][] for more informations. ### ngtcp2 The ngtcp2 and nghttp3 dependencies provide the core functionality for QUIC and HTTP/3. The sources are pulled from: * ngtcp2: <https://github.com/ngtcp2/ngtcp2> * nghttp3: <https://github.com/ngtcp2/nghttp3> In both the `ngtcp2` and `nghttp3` git repos, the active development occurs in the default branch (currently named `main` in each). Tagged versions do not always point to the default branch. We only use a subset of the sources for each. The `nghttp3` library depends on `ngtcp2`. Both should always be updated together. From `ngtcp2` we only want the contents of the `lib` and `crypto` directories; from `nghttp3` we only want the contents of the `lib` directory. ### npm The [npm](https://github.com/npm/cli) dependency is the package manager for JavaScript. New pull requests should be opened when a "next" version of npm has been released. Once the "next" version has been promoted to "latest" the PR should be updated as necessary. The specific Node.js release streams the new version will be able to land into are at the discretion of the release and LTS teams. This process only covers full updates to new versions of npm. Cherry-picked changes can be reviewed and landed via the normal consensus seeking process. ### openssl The [openssl](https://github.com/quictls/openssl) dependency is a fork of OpenSSL to enable QUIC. [OpenSSL](https://www.openssl.org/) is toolkit for general-purpose cryptography and secure communication. Node.js currently uses the quictls/openssl fork, which closely tracks the main openssl/openssl releases with the addition of APIs to support the QUIC protocol. See [maintaining-openssl][] for more informations. ### postject The [postject](https://github.com/nodejs/postject) dependency is used for the [Single Executable strategic initiative](https://github.com/nodejs/single-executable). ### simdutf 4.0.4 The [simdutf](https://github.com/simdutf/simdutf) dependency is a C++ library for fast UTF-8 decoding and encoding. ### undici 5.26.4 The [undici](https://github.com/nodejs/undici) dependency is an HTTP/1.1 client, written from scratch for Node.js.. See [maintaining-http][] for more informations. ### uv The [libuv](https://github.com/libuv/libuv) dependency is a multi-platform support library with a focus on asynchronous I/O. It was primarily developed for use by Node.js. ### uvwasi 0.0.19 The [uvwasi](https://github.com/nodejs/uvwasi) dependency implements the WASI system call API, so that WebAssembly runtimes can easily implement WASI calls. Under the hood, uvwasi leverages libuv where possible for maximum portability. See [maintaining-web-assembly][] for more informations. ### V8 [V8](https://chromium.googlesource.com/v8/v8.git/) is Google's open source high-performance JavaScript and WebAssembly engine, written in C++. See [maintaining-V8][] for more informations. ### zlib The [zlib](https://chromium.googlesource.com/chromium/src/+/refs/heads/main/third_party/zlib) dependency lossless data-compression library, it comes from the Chromium team's zlib fork which incorporated performance improvements not currently available in standard zlib. [acorn]: #acorn [ada]: #ada [base64]: #base64 [brotli]: #brotli [c-ares 1.20.1]: #c-ares-1200 [cjs-module-lexer]: #cjs-module-lexer [corepack]: #corepack [dependency-update-action]: ../../../.github/workflows/tools.yml [googletest 2dd1c13]: #googletest-2dd1c13 [histogram]: #histogram [icu-small]: #icu-small [llhttp]: #llhttp [maintaining-V8]: ./maintaining-V8.md [maintaining-cjs-module-lexer]: ./maintaining-cjs-module-lexer.md [maintaining-http]: ./maintaining-http.md [maintaining-icu]: ./maintaining-icu.md [maintaining-openssl]: ./maintaining-openssl.md [maintaining-web-assembly]: ./maintaining-web-assembly.md [minimatch]: #minimatch [nghttp2]: #nghttp2 [ngtcp2]: #ngtcp2 [npm]: #npm [openssl]: #openssl [postject]: #postject [simdutf 4.0.4]: #simdutf-404 [undici 5.26.4]: #undici-5264 [update-openssl-action]: ../../../.github/workflows/update-openssl.yml [uv]: #uv [uvwasi 0.0.19]: #uvwasi-0019 [v8]: #v8 [zlib]: #zlib