net: refactor check for Windows

PR-URL: #33497
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

lib/net.js

@@ -119,6 +119,8 @@ const { kTimeout } = require('internal/timers');
 const DEFAULT_IPV4_ADDR = '0.0.0.0';
 const DEFAULT_IPV6_ADDR = '::';
 
+const isWindows = process.platform === 'win32';
+
 function noop() {}
 
 function getFlags(ipv6Only) {
@@ -335,8 +337,7 @@ function Socket(options) {
       this[async_id_symbol] = this._handle.getAsyncId();
 
       if ((fd === 1 || fd === 2) &&
-          (this._handle instanceof Pipe) &&
-          process.platform === 'win32') {
+          (this._handle instanceof Pipe) && isWindows) {
         // Make stdout and stderr blocking on Windows
         err = this._handle.setBlocking(true);
         if (err)
@@ -1024,7 +1025,7 @@ function lookupAndConnect(self, options) {
     hints: options.hints || 0
   };
 
-  if (process.platform !== 'win32' &&
+  if (!isWindows &&
       dnsopts.family !== 4 &&
       dnsopts.family !== 6 &&
       dnsopts.hints === 0) {
@@ -1227,7 +1228,7 @@ function createServerHandle(address, port, addressType, fd, flags) {
     assert(!address && !port);
   } else if (port === -1 && addressType === -1) {
     handle = new Pipe(PipeConstants.SERVER);
-    if (process.platform === 'win32') {
+    if (isWindows) {
       const instances = parseInt(process.env.NODE_PENDING_PIPE_INSTANCES);
       if (!NumberIsNaN(instances)) {
         handle.setPendingInstances(instances);
@@ -1710,7 +1711,7 @@ Server.prototype.unref = function() {
 let _setSimultaneousAccepts;
 let warnSimultaneousAccepts = true;
 
-if (process.platform === 'win32') {
+if (isWindows) {
   let simultaneousAccepts;
 
   _setSimultaneousAccepts = function(handle) {