lib: more consistent use of module.exports = {} model

Switch to using the more efficient module.exports = {}
where possible.

PR-URL: #11406
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

lib/internal/buffer.js

@@ -12,7 +12,7 @@ const { isUint8Array } = process.binding('util');
 
 // Transcodes the Buffer from one encoding to another, returning a new
 // Buffer instance.
-exports.transcode = function transcode(source, fromEncoding, toEncoding) {
+function transcode(source, fromEncoding, toEncoding) {
   if (!isUint8Array(source))
     throw new TypeError('"source" argument must be a Buffer or Uint8Array');
   if (source.length === 0) return Buffer.alloc(0);
@@ -28,4 +28,8 @@ exports.transcode = function transcode(source, fromEncoding, toEncoding) {
   err.code = code;
   err.errno = result;
   throw err;
+}
+
+module.exports = {
+  transcode
 };

lib/internal/child_process.js

@@ -22,13 +22,6 @@ const errnoException = util._errnoException;
 const SocketListSend = SocketList.SocketListSend;
 const SocketListReceive = SocketList.SocketListReceive;
 
-module.exports = {
-  ChildProcess,
-  setupChannel,
-  _validateStdio,
-  getSocketList
-};
-
 // this object contain function to convert TCP objects to native handle objects
 // and back again.
 const handleConversion = {
@@ -900,3 +893,10 @@ function maybeClose(subprocess) {
     subprocess.emit('close', subprocess.exitCode, subprocess.signalCode);
   }
 }
+
+module.exports = {
+  ChildProcess,
+  setupChannel,
+  _validateStdio,
+  getSocketList
+};

lib/internal/fs.js

@@ -20,7 +20,6 @@ function assertEncoding(encoding) {
     throw new Error(`Unknown encoding: ${encoding}`);
   }
 }
-exports.assertEncoding = assertEncoding;
 
 function stringToFlags(flag) {
   if (typeof flag === 'number') {
@@ -54,7 +53,6 @@ function stringToFlags(flag) {
 
   throw new Error('Unknown file open flag: ' + flag);
 }
-exports.stringToFlags = stringToFlags;
 
 // Temporary hack for process.stdout and process.stderr when piped to files.
 function SyncWriteStream(fd, options) {
@@ -95,6 +93,9 @@ SyncWriteStream.prototype.destroy = function() {
   return true;
 };
 
-exports.SyncWriteStream = SyncWriteStream;
-
-exports.realpathCacheKey = Symbol('realpathCacheKey');
+module.exports = {
+  assertEncoding,
+  stringToFlags,
+  SyncWriteStream,
+  realpathCacheKey: Symbol('realpathCacheKey')
+};

lib/internal/net.js

@@ -1,7 +1,5 @@
 'use strict';
 
-module.exports = { isLegalPort, assertPort };
-
 // Check that the port number is not NaN when coerced to a number,
 // is an integer and that it falls within the legal range of port numbers.
 function isLegalPort(port) {
@@ -16,3 +14,8 @@ function assertPort(port) {
   if (typeof port !== 'undefined' && !isLegalPort(port))
     throw new RangeError('"port" argument must be >= 0 and < 65536');
 }
+
+module.exports = {
+  isLegalPort,
+  assertPort
+};