test: refactor test-dgram-broadcast-multi-process

* Add check that `signal` is not null in callback.
* Use arrow functions for callbacks, destructuring where appropriate,
  and a trailing comma in multi-line arrays

PR-URL: https://github.com/nodejs/node/pull/26846
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>

test/internet/test-dgram-broadcast-multi-process.js

@@ -28,14 +28,14 @@ const assert = require('assert');
 const dgram = require('dgram');
 const util = require('util');
 const networkInterfaces = require('os').networkInterfaces();
-const fork = require('child_process').fork;
+const { fork } = require('child_process');
 const LOCAL_BROADCAST_HOST = '255.255.255.255';
 const TIMEOUT = common.platformTimeout(5000);
 const messages = [
   Buffer.from('First message to send'),
   Buffer.from('Second message to send'),
   Buffer.from('Third message to send'),
-  Buffer.from('Fourth message to send')
+  Buffer.from('Fourth message to send'),
 ];
 
 let bindAddress = null;
@@ -65,7 +65,7 @@ if (process.argv[2] !== 'child') {
   let timer = null;
 
   // Exit the test if it doesn't succeed within TIMEOUT
-  timer = setTimeout(function() {
+  timer = setTimeout(() => {
     console.error('[PARENT] Responses were not received within %d ms.',
                   TIMEOUT);
     console.error('[PARENT] Fail');
@@ -84,7 +84,7 @@ if (process.argv[2] !== 'child') {
       worker.messagesReceived = [];
 
       // Handle the death of workers
-      worker.on('exit', function(code, signal) {
+      worker.on('exit', (code, signal) => {
         // Don't consider this the true death if the worker
         // has finished successfully
         // or if the exit code is 0
@@ -98,6 +98,8 @@ if (process.argv[2] !== 'child') {
                       dead,
                       listeners);
 
+        assert.notStrictEqual(signal, null);
+
         if (dead === listeners) {
           console.error('[PARENT] All workers have died.');
           console.error('[PARENT] Fail');
@@ -108,7 +110,7 @@ if (process.argv[2] !== 'child') {
         }
       });
 
-      worker.on('message', function(msg) {
+      worker.on('message', (msg) => {
         if (msg.listening) {
           listening += 1;
 
@@ -132,12 +134,12 @@ if (process.argv[2] !== 'child') {
                           'required number of ' +
                           'messages. Will now compare.');
 
-            Object.keys(workers).forEach(function(pid) {
+            Object.keys(workers).forEach((pid) => {
               const worker = workers[pid];
 
               let count = 0;
 
-              worker.messagesReceived.forEach(function(buf) {
+              worker.messagesReceived.forEach((buf) => {
                 for (let i = 0; i < messages.length; ++i) {
                   if (buf.toString() === messages[i].toString()) {
                     count++;
@@ -170,11 +172,11 @@ if (process.argv[2] !== 'child') {
   // Bind the address explicitly for sending
   // INADDR_BROADCAST to only one interface
   sendSocket.bind(common.PORT, bindAddress);
-  sendSocket.on('listening', function() {
+  sendSocket.on('listening', () => {
     sendSocket.setBroadcast(true);
   });
 
-  sendSocket.on('close', function() {
+  sendSocket.on('close', () => {
     console.error('[PARENT] sendSocket closed');
   });
 
@@ -192,7 +194,7 @@ if (process.argv[2] !== 'child') {
       buf.length,
       common.PORT,
       LOCAL_BROADCAST_HOST,
-      function(err) {
+      (err) => {
         assert.ifError(err);
         console.error('[PARENT] sent %s to %s:%s',
                       util.inspect(buf.toString()),
@@ -204,7 +206,7 @@ if (process.argv[2] !== 'child') {
   };
 
   function killSubprocesses(subprocesses) {
-    Object.keys(subprocesses).forEach(function(key) {
+    Object.keys(subprocesses).forEach((key) => {
       const subprocess = subprocesses[key];
       subprocess.kill();
     });
@@ -218,7 +220,7 @@ if (process.argv[2] === 'child') {
     reuseAddr: true
   });
 
-  listenSocket.on('message', function(buf, rinfo) {
+  listenSocket.on('message', (buf, rinfo) => {
     // Receive udp messages only sent from parent
     if (rinfo.address !== bindAddress) return;
 
@@ -232,24 +234,18 @@ if (process.argv[2] === 'child') {
     process.send({ message: buf.toString() });
 
     if (receivedMessages.length === messages.length) {
-      process.nextTick(function() {
-        listenSocket.close();
-      });
+      process.nextTick(() => { listenSocket.close(); });
     }
   });
 
-  listenSocket.on('close', function() {
+  listenSocket.on('close', () => {
     // HACK: Wait to exit the process to ensure that the parent
     // process has had time to receive all messages via process.send()
     // This may be indicative of some other issue.
-    setTimeout(function() {
-      process.exit();
-    }, 1000);
+    setTimeout(() => { process.exit(); }, 1000);
   });
 
-  listenSocket.on('listening', function() {
-    process.send({ listening: true });
-  });
+  listenSocket.on('listening', () => { process.send({ listening: true }); });
 
   listenSocket.bind(common.PORT);
 }