os: refactor os structure, add Symbol.toPrimitive

Refactor the structure of the os module to use more efficient
module.exports = {} pattern.
Add Symbol.toPrimitive support to os methods that return simple
primitives. This is a minor tweak that makes using these slightly
more friendly when doing things like:
```js
var m = `${os.tmpdir}/foo`
```
PR-URL: #12654
Reviewed-By: Daijiro Wachi <daijiro.wachi@gmail.com>
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

Author: jasnell

lib/os.js

@@ -21,31 +21,50 @@
 
 'use strict';
 
-constbinding=process.binding('os');
-constgetCPUs=binding.getCPUs;
-constgetLoadAvg=binding.getLoadAvg;
 constpushValToArrayMax=process.binding('util').pushValToArrayMax;
 constconstants=process.binding('constants').os;
-constinternalUtil=require('internal/util');
+constdeprecate=require('internal/util').deprecate;
 constisWindows=process.platform==='win32';
 
-exports.hostname=binding.getHostname;
-exports.uptime=binding.getUptime;
-exports.freemem=binding.getFreeMem;
-exports.totalmem=binding.getTotalMem;
-exports.type=binding.getOSType;
-exports.release=binding.getOSRelease;
-exports.networkInterfaces=binding.getInterfaceAddresses;
-exports.homedir=binding.getHomeDirectory;
-exports.userInfo=binding.getUserInfo;
+const{
+ getCPUs,
+ getFreeMem,
+ getHomeDirectory,
+ getHostname,
+ getInterfaceAddresses,
+ getLoadAvg,
+ getOSRelease,
+ getOSType,
+ getTotalMem,
+ getUserInfo,
+ getUptime,
+ isBigEndian
+}=process.binding('os');
+
+getFreeMem[Symbol.toPrimitive]=()=>getFreeMem();
+getHostname[Symbol.toPrimitive]=()=>getHostname();
+getHomeDirectory[Symbol.toPrimitive]=()=>getHomeDirectory();
+getOSRelease[Symbol.toPrimitive]=()=>getOSRelease();
+getOSType[Symbol.toPrimitive]=()=>getOSType();
+getTotalMem[Symbol.toPrimitive]=()=>getTotalMem();
+getUptime[Symbol.toPrimitive]=()=>getUptime();
+
+constkEndianness=isBigEndian ? 'BE' : 'LE';
+
+consttmpDirDeprecationMsg=
+'os.tmpDir() is deprecated. Use os.tmpdir() instead.';
+
+constgetNetworkInterfacesDepMsg=
+'os.getNetworkInterfaces is deprecated. Use os.networkInterfaces instead.';
 
 constavgValues=newFloat64Array(3);
-exports.loadavg=functionloadavg(){
+constcpuValues=newFloat64Array(6*pushValToArrayMax);
+
+functionloadavg(){
 getLoadAvg(avgValues);
 return[avgValues[0],avgValues[1],avgValues[2]];
-};
+}
 
-constcpuValues=newFloat64Array(6*pushValToArrayMax);
 functionaddCPUInfo(){
 for(vari=0,c=0;i<arguments.length;++i,c+=6){
 this[this.length]={
@@ -61,25 +80,22 @@ function addCPUInfo() {
 };
 }
 }
-exports.cpus=functioncpus(){
-returngetCPUs(addCPUInfo,cpuValues,[]);
-};
 
-Object.defineProperty(exports,'constants',{
-configurable: false,
-enumerable: true,
-value: constants
-});
+functioncpus(){
+returngetCPUs(addCPUInfo,cpuValues,[]);
+}
 
-exports.arch=function(){
+functionarch(){
 returnprocess.arch;
-};
+}
+arch[Symbol.toPrimitive]=()=>process.arch;
 
-exports.platform=function(){
+functionplatform(){
 returnprocess.platform;
-};
+}
+platform[Symbol.toPrimitive]=()=>process.platform;
 
-exports.tmpdir=function(){
+functiontmpdir(){
 varpath;
 if(isWindows){
 path=process.env.TEMP||
@@ -97,22 +113,41 @@ exports.tmpdir = function() {
 }
 
 returnpath;
-};
+}
+tmpdir[Symbol.toPrimitive]=()=>tmpdir();
 
-consttmpDirDeprecationMsg=
-'os.tmpDir() is deprecated. Use os.tmpdir() instead.';
-exports.tmpDir=internalUtil.deprecate(exports.tmpdir,
-tmpDirDeprecationMsg,
-'DEP0022');
+functionendianness(){
+returnkEndianness;
+}
+endianness[Symbol.toPrimitive]=()=>kEndianness;
 
-exports.getNetworkInterfaces=internalUtil.deprecate(function(){
-returnexports.networkInterfaces();
-},'os.getNetworkInterfaces is deprecated. '+
-'Use os.networkInterfaces instead.','DEP0023');
+module.exports=exports={
+ arch,
+ cpus,
+EOL: isWindows ? '\r\n' : '\n',
+ endianness,
+freemem: getFreeMem,
+homedir: getHomeDirectory,
+hostname: getHostname,
+ loadavg,
+networkInterfaces: getInterfaceAddresses,
+ platform,
+release: getOSRelease,
+ tmpdir,
+totalmem: getTotalMem,
+type: getOSType,
+userInfo: getUserInfo,
+uptime: getUptime,
 
-exports.EOL=isWindows ? '\r\n' : '\n';
+// Deprecated APIs
+getNetworkInterfaces: deprecate(getInterfaceAddresses,
+getNetworkInterfacesDepMsg,
+'DEP0023'),
+tmpDir: deprecate(tmpdir,tmpDirDeprecationMsg,'DEP0022')
+};
 
-if(binding.isBigEndian)
-exports.endianness=function(){return'BE';};
-else
-exports.endianness=function(){return'LE';};
+Object.defineProperty(module.exports,'constants',{
+configurable: false,
+enumerable: true,
+value: constants
+});

test/parallel/test-os.js

@@ -191,3 +191,12 @@ is.string(pwd.username);
 assert.ok(pwd.homedir.includes(path.sep));
 assert.strictEqual(pwd.username,pwdBuf.username.toString('utf8'));
 assert.strictEqual(pwd.homedir,pwdBuf.homedir.toString('utf8'));
+
+// Test that the Symbol.toPrimitive functions work correctly
+[
+[`${os.hostname}`,os.hostname()],
+[`${os.homedir}`,os.homedir()],
+[`${os.release}`,os.release()],
+[`${os.type}`,os.type()],
+[`${os.endianness}`,os.endianness()]
+].forEach((set)=>assert.strictEqual(set[0],set[1]));