test: refactor test-dgram-bind-shared-ports.js

Refactored the code to latest standards, where all var is
changed to const, functions are changed to arrow functions
and assert.equal chaned to assert.strictEqual

PR-URL: https://github.com/nodejs/node/pull/8582
Reviewed-By: Robert Jefe Lindstaedt <robert.lindstaedt@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Ilkka Myller <ilkka.myller@nodefield.com>

test/parallel/test-dgram-bind-shared-ports.js

@@ -1,17 +1,17 @@
 'use strict';
-var common = require('../common');
+const common = require('../common');
-var assert = require('assert');
+const assert = require('assert');
-var cluster = require('cluster');
+const cluster = require('cluster');
-var dgram = require('dgram');
+const dgram = require('dgram');
 
-function noop() {}
+function noop() { }
 
 if (cluster.isMaster) {
-  var worker1 = cluster.fork();
+  const worker1 = cluster.fork();
 
   if (common.isWindows) {
-    var checkErrType = function(er) {
+    const checkErrType = (er) => {
-      assert.equal(er.code, 'ENOTSUP');
+      assert.strictEqual(er.code, 'ENOTSUP');
       worker1.kill();
     };
 
@@ -19,26 +19,26 @@ if (cluster.isMaster) {
     return;
   }
 
-  worker1.on('message', function(msg) {
+  worker1.on('message', (msg) => {
-    assert.equal(msg, 'success');
+    assert.strictEqual(msg, 'success');
-    var worker2 = cluster.fork();
+    const worker2 = cluster.fork();
 
-    worker2.on('message', function(msg) {
+    worker2.on('message', (msg) => {
-      assert.equal(msg, 'socket2:EADDRINUSE');
+      assert.strictEqual(msg, 'socket2:EADDRINUSE');
       worker1.kill();
       worker2.kill();
     });
   });
 } else {
-  var socket1 = dgram.createSocket('udp4', noop);
+  const socket1 = dgram.createSocket('udp4', noop);
-  var socket2 = dgram.createSocket('udp4', noop);
+  const socket2 = dgram.createSocket('udp4', noop);
 
-  socket1.on('error', function(err) {
+  socket1.on('error', (err) => {
     // no errors expected
     process.send('socket1:' + err.code);
   });
 
-  socket2.on('error', function(err) {
+  socket2.on('error', (err) => {
     // an error is expected on the second worker
     process.send('socket2:' + err.code);
   });
@@ -47,8 +47,8 @@ if (cluster.isMaster) {
     address: 'localhost',
     port: common.PORT,
     exclusive: false
-  }, function() {
+  }, () => {
-    socket2.bind({port: common.PORT + 1, exclusive: true}, function() {
+    socket2.bind({ port: common.PORT + 1, exclusive: true }, () => {
       // the first worker should succeed
       process.send('success');
     });