node:os

node:os matches Node’s os.

Example

// os.mjs
import os from "node:os";

console.log(JSON.stringify(os.EOL), os.devNull);
console.log(os.constants.signals.SIGTERM, os.constants.errno.ENOENT);
console.log(os.availableParallelism() > 0, os.cpus().length > 0);
console.log(typeof os.totalmem(), typeof os.homedir(), os.endianness());

utf-8 · js · Lines: 7

elide run os.mjs prints:

text

"\n" /dev/null
15 2
true true
number string LE

utf-8 · text · Lines: 4

Differences from Node

cpus() reports each core’s model and speed; every times field is zero.

Reference

Status: Full · Not measured · since 1.1.0

Exports

Export	Kind	Status	Notes
`arch()`	function	Full	Returns the CPU architecture of the process (e.g. “x64”, “arm64”)
`cpus()`	function	Full	Returns an array of objects describing each logical CPU core
`endianness()`	function	Full	Returns the endianness of the CPU: “BE” (big-endian) or “LE” (little-endian)
`freemem()`	function	Full	Returns the amount of free system memory in bytes
`homedir()`	function	Full	Returns the current user’s home directory path
`hostname()`	function	Full	Returns the host name of the operating system
`loadavg()`	function	Full	Returns the 1, 5, and 15-minute system load averages
`networkInterfaces()`	function	Full	Returns an object mapping interface names to their address entries
`platform()`	function	Full	Returns the operating system platform (e.g. “linux”, “darwin”, “win32”)
`release()`	function	Full	Returns the OS release version string
`tmpdir()`	function	Full	Returns the operating system’s default directory for temporary files
`totalmem()`	function	Full	Returns the total amount of system memory in bytes
`type()`	function	Full	Returns the OS name (e.g. “Linux”, “Darwin”, “Windows_NT”)
`uptime()`	function	Full	Returns the system uptime in seconds
`userInfo()`	function	Full	Returns information about the currently effective user
`machine()`	function	Full	Returns the machine type as a string, such as “arm64”, “x86_64”, etc
`version()`	function	Full	Returns the operating system kernel version string
`availableParallelism()`	function	Full	Returns an estimate of the default amount of parallelism a program should use, respecting cgroups and CPU…
`getPriority()`	function	Full	Returns the scheduling priority for the process specified by pid
`setPriority()`	function	Full	Sets the scheduling priority for the process specified by pid
`EOL`	property	Full	The operating system end-of-line character sequence (`\n` on POSIX, `\r\n` on Windows)
`devNull`	property	Full	The null device path (`/dev/null` on POSIX, `\\.\nul` on Windows)
`constants`	property	Full	Object containing signal, errno, dlopen, and priority constants
`os.constants.signals`	constant	Full	`SIGHUP`, `SIGINT`, `SIGQUIT`, `SIGILL`, `SIGTRAP`, `SIGABRT` and 27 more
`os.constants.errno`	constant	Full	`EPERM`, `ENOENT`, `ESRCH`, `EINTR`, `EIO`, `ENXIO` and 81 more
`os.constants.dlopen`	constant	Full	`RTLD_LAZY`, `RTLD_NOW`, `RTLD_GLOBAL`, `RTLD_LOCAL`, `RTLD_DEEPBIND`
`os.constants.priority`	constant	Full	`PRIORITY_LOW`, `PRIORITY_BELOW_NORMAL`, `PRIORITY_NORMAL`, `PRIORITY_ABOVE_NORMAL`, `PRIORITY_HIGH`, `PRIORITY_HIGHEST`
`os.constants`	constant	Full	`UV_UDP_REUSEADDR`