nodejs/doc/api/globals.markdown

Global Objects

These objects are available in all modules. Some of these objects aren't actually in the global scope but in the module scope - this will be noted.

global

• {Object} The global namespace object.

In browsers, the top-level scope is the global scope. That means that in browsers if you're in the global scope var something will define a global variable. In Node this is different. The top-level scope is not the global scope; var something inside a Node module will be local to that module.

process

• {Object}

The process object. See the process object section.

console

• {Object}

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

Class: Buffer

• {Function}

Used to handle binary data. See the buffer section

require()

• {Function}

To require modules. See the Modules section. require isn't actually a global but rather local to each module.

require.resolve()

Use the internal require() machinery to look up the location of a module, but rather than loading the module, just return the resolved filename.

require.cache

• {Object}

Modules are cached in this object when they are required. By deleting a key value from this object, the next require will reload the module.

require.extensions

Stability: 0 - Deprecated

• {Object}

Instruct require on how to handle certain file extensions.

Process files with the extension .sjs as .js:

require.extensions['.sjs'] = require.extensions['.js'];

Deprecated In the past, this list has been used to load non-JavaScript modules into Node by compiling them on-demand. However, in practice, there are much better ways to do this, such as loading modules via some other Node program, or compiling them to JavaScript ahead of time.

Since the Module system is locked, this feature will probably never go away. However, it may have subtle bugs and complexities that are best left untouched.

__filename

• {String}

The filename of the code being executed. This is the resolved absolute path of this code file. For a main program this is not necessarily the same filename used in the command line. The value inside a module is the path to that module file.

Example: running node example.js from /Users/mjr

console.log(__filename);
// /Users/mjr/example.js

__filename isn't actually a global but rather local to each module.

__dirname

• {String}

The name of the directory that the currently executing script resides in.

Example: running node example.js from /Users/mjr

console.log(__dirname);
// /Users/mjr

__dirname isn't actually a global but rather local to each module.

module

• {Object}

A reference to the current module. In particular module.exports is used for defining what a module exports and makes available through require().

module isn't actually a global but rather local to each module.

See the module system documentation for more information.

exports

A reference to the module.exports that is shorter to type. See module system documentation for details on when to use exports and when to use module.exports.

exports isn't actually a global but rather local to each module.

See the module system documentation for more information.

See the module section for more information.

setTimeout(cb, ms)

Run callback cb after at least ms milliseconds. The actual delay depends on external factors like OS timer granularity and system load.

The timeout must be in the range of 1-2,147,483,647 inclusive. If the value is outside that range, it's changed to 1 millisecond. Broadly speaking, a timer cannot span more than 24.8 days.

Returns an opaque value that represents the timer.

clearTimeout(t)

Stop a timer that was previously created with setTimeout(). The callback will not execute.

setInterval(cb, ms)

Run callback cb repeatedly every ms milliseconds. Note that the actual interval may vary, depending on external factors like OS timer granularity and system load. It's never less than ms but it may be longer.

The interval must be in the range of 1-2,147,483,647 inclusive. If the value is outside that range, it's changed to 1 millisecond. Broadly speaking, a timer cannot span more than 24.8 days.

Returns an opaque value that represents the timer.

clearInterval(t)

Stop a timer that was previously created with setInterval(). The callback will not execute.

The timer functions are global variables. See the timers section.