cpu-arch

cpu-arch

Detect CPU architecture (not process architecture).

Handles emulation scenarios where process.arch returns the wrong value:

• Windows WoW64: 32-bit Node on 64-bit Windows → returns x64
• macOS Rosetta 2: x64 Node on Apple Silicon → returns arm64
• Windows ARM64: Any Node on ARM Windows → returns arm64

Installation

npm install cpu-arch

Usage

const cpuArch = require('cpu-arch');

console.log(cpuArch());
// => 'x64', 'arm64', 'ia32', 'arm', etc.

Why Not process.arch?

process.arch returns the architecture of the Node.js binary, not the CPU:

Scenario	process.arch	cpuArch()
32-bit Node on 64-bit Windows	ia32	x64
x64 Node on Apple Silicon (Rosetta)	x64	arm64
Native arm64 Node on Apple Silicon	arm64	arm64

This matters when selecting native binaries (e.g., @swc/core, Node.js downloads).

Return Values

Value	Description
x64	64-bit Intel/AMD
arm64	64-bit ARM (Apple Silicon, ARM64 Windows/Linux)
ia32	32-bit Intel/AMD
arm	32-bit ARM
ia64	Intel Itanium
Other	Raw uname -m output (ppc64, s390x, etc.)

Platform Detection Methods

Platform	Method
Windows	PROCESSOR_ARCHITEW6432 / PROCESSOR_ARCHITECTURE env vars
macOS	sysctl -in sysctl.proc_translated for Rosetta detection
Linux	uname -m

License

MIT