Node.js v18.20.1 documentation

os.EOL#

• <string>

The operating system-specific end-of-line marker.

• \n on POSIX
• \r\n on Windows

os.availableParallelism()#

• Returns: <integer>

Returns an estimate of the default amount of parallelism a program should use. Always returns a value greater than zero.

This function is a small wrapper about libuv's uv_available_parallelism().

os.arch()#

• Returns: <string>

Returns the operating system CPU architecture for which the Node.js binary was compiled. Possible values are 'arm', 'arm64', 'ia32', 'mips', 'mipsel', 'ppc', 'ppc64', 's390', 's390x', and 'x64'.

The return value is equivalent to process.arch.

os.constants#

• <Object>

Contains commonly used operating system-specific constants for error codes, process signals, and so on. The specific constants defined are described in OS constants.

os.cpus()#

• Returns: <Object[]>

Returns an array of objects containing information about each logical CPU core. The array will be empty if no CPU information is available, such as if the /proc file system is unavailable.

The properties included on each object include:

• model <string>
• speed <number> (in MHz)
• times <Object>
  • user <number> The number of milliseconds the CPU has spent in user mode.
  • nice <number> The number of milliseconds the CPU has spent in nice mode.
  • sys <number> The number of milliseconds the CPU has spent in sys mode.
  • idle <number> The number of milliseconds the CPU has spent in idle mode.
  • irq <number> The number of milliseconds the CPU has spent in irq mode.

[
  {
    model: 'Intel(R) Core(TM) i7 CPU         860  @ 2.80GHz',
    speed: 2926,
    times: {
      user: 252020,
      nice: 0,
      sys: 30340,
      idle: 1070356870,
      irq: 0,
    },
  },
  {
    model: 'Intel(R) Core(TM) i7 CPU         860  @ 2.80GHz',
    speed: 2926,
    times: {
      user: 306960,
      nice: 0,
      sys: 26980,
      idle: 1071569080,
      irq: 0,
    },
  },
  {
    model: 'Intel(R) Core(TM) i7 CPU         860  @ 2.80GHz',
    speed: 2926,
    times: {
      user: 248450,
      nice: 0,
      sys: 21750,
      idle: 1070919370,
      irq: 0,
    },
  },
  {
    model: 'Intel(R) Core(TM) i7 CPU         860  @ 2.80GHz',
    speed: 2926,
    times: {
      user: 256880,
      nice: 0,
      sys: 19430,
      idle: 1070905480,
      irq: 20,
    },
  },
] copy

nice values are POSIX-only. On Windows, the nice values of all processors are always 0.

os.cpus().length should not be used to calculate the amount of parallelism available to an application. Use os.availableParallelism() for this purpose.

os.devNull#

• <string>

The platform-specific file path of the null device.

• \\.\nul on Windows
• /dev/null on POSIX

os.endianness()#

• Returns: <string>

Returns a string identifying the endianness of the CPU for which the Node.js binary was compiled.

Possible values are 'BE' for big endian and 'LE' for little endian.

os.freemem()#

• Returns: <integer>

Returns the amount of free system memory in bytes as an integer.

os.getPriority([pid])#

• pid <integer> The process ID to retrieve scheduling priority for. Default: 0.
• Returns: <integer>

Returns the scheduling priority for the process specified by pid. If pid is not provided or is 0, the priority of the current process is returned.

os.homedir()#

• Returns: <string>

Returns the string path of the current user's home directory.

On POSIX, it uses the $HOME environment variable if defined. Otherwise it uses the effective UID to look up the user's home directory.

On Windows, it uses the USERPROFILE environment variable if defined. Otherwise it uses the path to the profile directory of the current user.

os.hostname()#

• Returns: <string>

Returns the host name of the operating system as a string.

os.loadavg()#