Node.js

- About these Docs
- Usage & Example

- Assertion Testing
- Buffer
- C/C++ Addons
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- DNS
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- File System
- Globals
- HTTP
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- Process
- Punycode
- Query Strings
- Readline
- REPL
- Stream
- String Decoder
- Timers
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- Utilities
- V8
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- GitHub Repo & Issue Tracker
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# About this Documentation#

The goal of this documentation is to comprehensively explain the Node.js API, both from a reference as well as a conceptual point of view. Each section describes a built-in module or high-level concept.

Where appropriate, property types, method arguments, and the arguments provided to event handlers are detailed in a list underneath the topic heading.

Every `.html` document has a corresponding `.json` document presenting the same information in a structured manner. This feature is experimental, and added for the benefit of IDEs and other utilities that wish to do programmatic things with the documentation.

Every `.html` and `.json` file is generated based on the corresponding `.md` file in the `doc/api/` folder in Node.js's source tree. The documentation is generated using the `tools/doc/generate.js` program. The HTML template is located at `doc/template.html`.

If you find an error in this documentation, please submit an issue or see the contributing guide for directions on how to submit a patch.

## Stability Index#

Throughout the documentation, you will see indications of a section's stability. The Node.js API is still somewhat changing, and as it matures, certain parts are more reliable than others. Some are so proven, and so relied upon, that they are unlikely to ever change at all. Others are brand new and experimental, or known to be hazardous and in the process of being redesigned.

The stability indices are as follows:

    Stability: 0 - Deprecated
    This feature is known to be problematic, and changes are
    planned.  Do not rely on it.  Use of the feature may cause warnings.  Backwards
    compatibility should not be expected.

    Stability: 1 - Experimental
    This feature is subject to change, and is gated by a command line flag.
    It may change or be removed in future versions.

    Stability: 2 - Stable
    The API has proven satisfactory. Compatibility with the npm ecosystem
    is a high priority, and will not be broken unless absolutely necessary.

    Stability: 3 - Locked
    Only fixes related to security, performance, or bug fixes will be accepted.
    Please do not suggest API changes in this area; they will be refused.

## JSON Output#

    Stability: 1 - Experimental

Every HTML file in the markdown has a corresponding JSON file with the same data.

This feature was added in Node.js v0.6.12. It is experimental.

## Syscalls and man pages#

System calls like open(2) and read(2) define the interface between user programs and the underlying operating system. Node functions which simply wrap a syscall, like `fs.open()`, will document that. The docs link to the corresponding man pages (short for manual pages) which describe how the syscalls work.

Caveat: some syscalls, like lchown(2), are BSD-specific. That means, for example, that `fs.lchown()` only works on Mac OS X and other BSD-derived systems, and is not available on Linux.

Most Unix syscalls have Windows equivalents, but behavior may differ on Windows relative to Linux and OS X. For an example of the subtle ways in which it's sometimes impossible to replace Unix syscall semantics on Windows, see Node issue 4760.