Node.js

- About this documentation
- Usage and example

- Assertion testing
- Async hooks
- Buffer
- C++ addons
- C/C++ addons with N-API
- C++ embedder API
- Child processes
- Cluster
- Command-line options
- Console
- Crypto
- Debugger
- Deprecated APIs
- DNS
- Domain
- Errors
- Events
- File system
- Globals
- HTTP
- HTTP/2
- HTTPS
- Inspector
- Internationalization
- Modules: CommonJS modules
- Modules: ECMAScript modules
- Modules: `module` API
- Modules: Packages
- Net
- OS
- Path
- Performance hooks
- Policies
- Process
- Punycode
- Query strings
- Readline
- REPL
- Report
- Stream
- String decoder
- Timers
- TLS/SSL
- Trace events
- TTY
- UDP/datagram
- URL
- Utilities
- V8
- VM
- WASI
- Worker threads
- Zlib

- Code repository and issue tracker

# Global objects#

These objects are available in all modules. The following variables may appear to be global but are not. They exist only in the scope of modules, see the module system documentation:

- `__dirname`
- `__filename`
- `exports`
- `module`
- `require()`

The objects listed here are specific to Node.js. There are built-in objects that are part of the JavaScript language itself, which are also globally accessible.

## Class: `Buffer`#

Added in: v0.1.103

- <Function>

Used to handle binary data. See the buffer section.

## `__dirname`#

This variable may appear to be global but is not. See `__dirname`.

## `__filename`#

This variable may appear to be global but is not. See `__filename`.

## `clearImmediate(immediateObject)`#

Added in: v0.9.1

`clearImmediate` is described in the timers section.

## `clearInterval(intervalObject)`#

Added in: v0.0.1

`clearInterval` is described in the timers section.

## `clearTimeout(timeoutObject)`#

Added in: v0.0.1

`clearTimeout` is described in the timers section.

## `console`#

Added in: v0.1.100

- <Object>

Used to print to stdout and stderr. See the `console` section.

## `exports`#

This variable may appear to be global but is not. See `exports`.

## `global`#

Added in: v0.1.27

- <Object> The global namespace object.

In browsers, the top-level scope is the global scope. This means that within the browser `var something` will define a new global variable. In Node.js this is different. The top-level scope is not the global scope; `var something` inside a Node.js module will be local to that module.

## `module`#

This variable may appear to be global but is not. See `module`.

## `process`#

Added in: v0.1.7

- <Object>

The process object. See the `process` object section.

## `queueMicrotask(callback)`#

Added in: v11.0.0

- `callback` <Function> Function to be queued.

The `queueMicrotask()` method queues a microtask to invoke `callback`. If `callback` throws an exception, the `process` object `'uncaughtException'` event will be emitted.

The microtask queue is managed by V8 and may be used in a similar manner to the `process.nextTick()` queue, which is managed by Node.js. The `process.nextTick()` queue is always processed before the microtask queue within each turn of the Node.js event loop.

    // Here, `queueMicrotask()` is used to ensure the 'load' event is always
    // emitted asynchronously, and therefore consistently. Using
    // `process.nextTick()` here would result in the 'load' event always emitting
    // before any other promise jobs.

    DataHandler.prototype.load = async function load(key) {
      const hit = this._cache.get(url);
      if (hit !== undefined) {
        queueMicrotask(() => {
          this.emit('load', hit);
        });
        return;
      }

      const data = await fetchData(key);
      this._cache.set(url, data);
      this.emit('load', data);
    };

## `require()`#

This variable may appear to be global but is not. See `require()`.

## `setImmediate(callback[, ...args])`#

Added in: v0.9.1

`setImmediate` is described in the timers section.

## `setInterval(callback, delay[, ...args])`#

Added in: v0.0.1

`setInterval` is described in the timers section.

## `setTimeout(callback, delay[, ...args])`#

Added in: v0.0.1

`setTimeout` is described in the timers section.

## `TextDecoder`#

Added in: v11.0.0

The WHATWG `TextDecoder` class. See the `TextDecoder` section.

## `TextEncoder`#

Added in: v11.0.0

The WHATWG `TextEncoder` class. See the `TextEncoder` section.

## `URL`#

Added in: v10.0.0

The WHATWG `URL` class. See the `URL` section.

## `URLSearchParams`#

Added in: v10.0.0

The WHATWG `URLSearchParams` class. See the `URLSearchParams` section.

## `WebAssembly`#

Added in: v8.0.0

- <Object>

The object that acts as the namespace for all W3C WebAssembly related functionality. See the Mozilla Developer Network for usage and compatibility.