os: add machine method

doc/api/os.md

@@ -452,6 +452,22 @@ On POSIX systems, the operating system release is determined by calling
 available, `GetVersionExW()` will be used. See
 <https://en.wikipedia.org/wiki/Uname#Examples> for more information.
 
+## `os.machine()`
+
+<!-- YAML
+added: REPLACEME
+-->
+
+* Returns {string}
+
+Returns the machine type as a string, such as `arm`, `aarch64`, `mips`,
+`mips64`, `ppc64`, `ppc64le`, `s390`, `s390x`, `i386`, `i686`, `x86_64`.
+
+On POSIX systems, the machine type is determined by calling
+[`uname(3)`][]. On Windows, `RtlGetVersion()` is used, and if it is not
+available, `GetVersionExW()` will be used. See
+<https://en.wikipedia.org/wiki/Uname#Examples> for more information.
+
 ## OS constants
 
 The following constants are exported by `os.constants`.

lib/os.js

@@ -75,6 +75,7 @@ const {
   0: type,
   1: version,
   2: release,
+  3: machine,
 } = _getOSInformation();
 
 const getHomeDirectory = getCheckedFunction(_getHomeDirectory);
@@ -92,12 +93,17 @@ const getOSType = () => type;
  * @returns {string}
  */
 const getOSVersion = () => version;
+/**
+ * @returns {string}
+ */
+const getMachine = () => machine;
 
 getFreeMem[SymbolToPrimitive] = () => getFreeMem();
 getHostname[SymbolToPrimitive] = () => getHostname();
 getOSVersion[SymbolToPrimitive] = () => getOSVersion();
 getOSType[SymbolToPrimitive] = () => getOSType();
 getOSRelease[SymbolToPrimitive] = () => getOSRelease();
+getMachine[SymbolToPrimitive] = () => getMachine();
 getHomeDirectory[SymbolToPrimitive] = () => getHomeDirectory();
 getTotalMem[SymbolToPrimitive] = () => getTotalMem();
 getUptime[SymbolToPrimitive] = () => getUptime();
@@ -367,7 +373,8 @@ module.exports = {
   type: getOSType,
   userInfo,
   uptime: getUptime,
-  version: getOSVersion
+  version: getOSVersion,
+  machine: getMachine,
 };
 
 ObjectDefineProperties(module.exports, {

src/node_os.cc

@@ -86,12 +86,12 @@ static void GetOSInformation(const FunctionCallbackInfo<Value>& args) {
     return args.GetReturnValue().SetUndefined();
   }
 
-  // [sysname, version, release]
+  // [sysname, version, release, machine]
   Local<Value> osInformation[] = {
-    String::NewFromUtf8(env->isolate(), info.sysname).ToLocalChecked(),
-    String::NewFromUtf8(env->isolate(), info.version).ToLocalChecked(),
-    String::NewFromUtf8(env->isolate(), info.release).ToLocalChecked()
-  };
+      String::NewFromUtf8(env->isolate(), info.sysname).ToLocalChecked(),
+      String::NewFromUtf8(env->isolate(), info.version).ToLocalChecked(),
+      String::NewFromUtf8(env->isolate(), info.release).ToLocalChecked(),
+      String::NewFromUtf8(env->isolate(), info.machine).ToLocalChecked()};
 
   args.GetReturnValue().Set(Array::New(env->isolate(),
                                        osInformation,

test/parallel/test-os.js

@@ -245,7 +245,7 @@ assert.strictEqual(`${os.tmpdir}`, os.tmpdir());
 assert.strictEqual(`${os.arch}`, os.arch());
 assert.strictEqual(`${os.platform}`, os.platform());
 assert.strictEqual(`${os.version}`, os.version());
-
+assert.strictEqual(`${os.machine}`, os.machine());
 assert.strictEqual(+os.totalmem, os.totalmem());
 
 // Assert that the following values are coercible to numbers.