- Assertion testing
- Async hooks
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- DNS
- Domain
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- Events
- File system
- Globals
- HTTP
- HTTP/2
- HTTPS
- Inspector
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- Modules: CommonJS modules
- Modules: ECMAScript modules
- Modules:
module
API - Modules: Packages
- Net
- OS
- Path
- Performance hooks
- Policies
- Process
- Punycode
- Query strings
- Readline
- REPL
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- Stream
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- V8
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Node.js v12.22.3 Documentation
Table of Contents
- Global objects
- Class:
Buffer
__dirname
__filename
clearImmediate(immediateObject)
clearInterval(intervalObject)
clearTimeout(timeoutObject)
console
exports
global
module
process
queueMicrotask(callback)
require()
setImmediate(callback[, ...args])
setInterval(callback, delay[, ...args])
setTimeout(callback, delay[, ...args])
TextDecoder
TextEncoder
URL
URLSearchParams
WebAssembly
- Class:
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:
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
#
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)
#
clearImmediate
is described in the timers section.
clearInterval(intervalObject)
#
clearInterval
is described in the timers section.
clearTimeout(timeoutObject)
#
clearTimeout
is described in the timers section.
console
#
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
#
- <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
#
The process object. See the process
object section.
queueMicrotask(callback)
#
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])
#
setImmediate
is described in the timers section.
setInterval(callback, delay[, ...args])
#
setInterval
is described in the timers section.
setTimeout(callback, delay[, ...args])
#
setTimeout
is described in the timers section.
TextDecoder
#
The WHATWG TextDecoder
class. See the TextDecoder
section.
TextEncoder
#
The WHATWG TextEncoder
class. See the TextEncoder
section.
URL
#
The WHATWG URL
class. See the URL
section.
URLSearchParams
#
The WHATWG URLSearchParams
class. See the URLSearchParams
section.
WebAssembly
#
The object that acts as the namespace for all W3C WebAssembly related functionality. See the Mozilla Developer Network for usage and compatibility.