process: internal/process/stdio.js cleanup / modernization

Avoid using deprecated getter syntax plus other
miscellaneous updates.

PR-URL: #6766
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

lib/internal/process/stdio.js

@@ -5,45 +5,41 @@ exports.setup = setupStdio;
 function setupStdio() {
   var stdin, stdout, stderr;
 
-  process.__defineGetter__('stdout', function() {
+  function getStdout() {
     if (stdout) return stdout;
     stdout = createWritableStdioStream(1);
     stdout.destroy = stdout.destroySoon = function(er) {
       er = er || new Error('process.stdout cannot be closed.');
       stdout.emit('error', er);
     };
     if (stdout.isTTY) {
-      process.on('SIGWINCH', function() {
-        stdout._refreshSize();
-      });
+      process.on('SIGWINCH', () => stdout._refreshSize());
     }
     return stdout;
-  });
+  }
 
-  process.__defineGetter__('stderr', function() {
+  function getStderr() {
     if (stderr) return stderr;
     stderr = createWritableStdioStream(2);
     stderr.destroy = stderr.destroySoon = function(er) {
       er = er || new Error('process.stderr cannot be closed.');
       stderr.emit('error', er);
     };
     if (stderr.isTTY) {
-      process.on('SIGWINCH', function() {
-        stderr._refreshSize();
-      });
+      process.on('SIGWINCH', () => stderr._refreshSize());
     }
     return stderr;
-  });
+  }
 
-  process.__defineGetter__('stdin', function() {
+  function getStdin() {
     if (stdin) return stdin;
 
-    var tty_wrap = process.binding('tty_wrap');
-    var fd = 0;
+    const tty_wrap = process.binding('tty_wrap');
+    const fd = 0;
 
     switch (tty_wrap.guessHandleType(fd)) {
       case 'TTY':
-        var tty = require('tty');
+        const tty = require('tty');
         stdin = new tty.ReadStream(fd, {
           highWaterMark: 0,
           readable: true,
@@ -52,13 +48,13 @@ function setupStdio() {
         break;
 
       case 'FILE':
-        var fs = require('fs');
+        const fs = require('fs');
         stdin = new fs.ReadStream(null, { fd: fd, autoClose: false });
         break;
 
       case 'PIPE':
       case 'TCP':
-        var net = require('net');
+        const net = require('net');
 
         // It could be that process has been started with an IPC channel
         // sitting on fd=0, in such case the pipe for this fd is already
@@ -100,7 +96,7 @@ function setupStdio() {
 
     // if the user calls stdin.pause(), then we need to stop reading
     // immediately, so that the process can close down.
-    stdin.on('pause', function() {
+    stdin.on('pause', () => {
       if (!stdin._handle)
         return;
       stdin._readableState.reading = false;
@@ -109,6 +105,24 @@ function setupStdio() {
     });
 
     return stdin;
+  }
+
+  Object.defineProperty(process, 'stdout', {
+    configurable: true,
+    enumerable: true,
+    get: getStdout
+  });
+
+  Object.defineProperty(process, 'stderr', {
+    configurable: true,
+    enumerable: true,
+    get: getStderr
+  });
+
+  Object.defineProperty(process, 'stdin', {
+    configurable: true,
+    enumerable: true,
+    get: getStdin
   });
 
   process.openStdin = function() {
@@ -119,26 +133,26 @@ function setupStdio() {
 
 function createWritableStdioStream(fd) {
   var stream;
-  var tty_wrap = process.binding('tty_wrap');
+  const tty_wrap = process.binding('tty_wrap');
 
   // Note stream._type is used for test-module-load-list.js
 
   switch (tty_wrap.guessHandleType(fd)) {
     case 'TTY':
-      var tty = require('tty');
+      const tty = require('tty');
       stream = new tty.WriteStream(fd);
       stream._type = 'tty';
       break;
 
     case 'FILE':
-      var fs = require('fs');
+      const fs = require('fs');
       stream = new fs.SyncWriteStream(fd, { autoClose: false });
       stream._type = 'fs';
       break;
 
     case 'PIPE':
     case 'TCP':
-      var net = require('net');
+      const net = require('net');
       stream = new net.Socket({
         fd: fd,
         readable: false,