test,lib,doc: use function declarations

Replace function expressions with function declarations in preparation
for a lint rule requiring function declarations.

PR-URL: https://github.com/nodejs/node/pull/12711
Reviewed-By: Vse Mozhet Byt <vsemozhetbyt@gmail.com>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

35 files changed, 120 insertions, 124 deletions

diff --git a/test/addons-napi/test_async/test.js b/test/addons-napi/test_async/test.js
index 7c140d79fc..2b4577624a 100644
--- a/test/addons-napi/test_async/test.js
+++ b/test/addons-napi/test_async/test.js
@@ -6,8 +6,7 @@ const test_async = require(`./build/${common.buildType}/test_async`);
 test_async.Test(5, common.mustCall(function(err, val) {
   assert.strictEqual(err, null);
   assert.strictEqual(val, 10);
-  process.nextTick(common.mustCall(function() {}));
+  process.nextTick(common.mustCall());
 }));
 
-const cancelSuceeded = function() {};
-test_async.TestCancel(common.mustCall(cancelSuceeded));
+test_async.TestCancel(common.mustCall());
diff --git a/test/addons-napi/test_exception/test.js b/test/addons-napi/test_exception/test.js
index 83d2b5000e..94f9566a4b 100644
--- a/test/addons-napi/test_exception/test.js
+++ b/test/addons-napi/test_exception/test.js
@@ -4,12 +4,12 @@ const common = require('../../common');
 const test_exception = require(`./build/${common.buildType}/test_exception`);
 const assert = require('assert');
 const theError = new Error('Some error');
-const throwTheError = function() {
+function throwTheError() {
   throw theError;
-};
+}
 let caughtError;
 
-const throwNoError = function() {};
+const throwNoError = common.noop;
 
 // Test that the native side successfully captures the exception
 let returnedError = test_exception.returnException(throwTheError);
diff --git a/test/addons-napi/test_instanceof/test.js b/test/addons-napi/test_instanceof/test.js
index 38d17031e9..418149d190 100644
--- a/test/addons-napi/test_instanceof/test.js
+++ b/test/addons-napi/test_instanceof/test.js
@@ -57,14 +57,14 @@ if (typeof Symbol !== 'undefined' && 'hasInstance' in Symbol &&
       (theObject instanceof theConstructor));
   }
 
-  const MyClass = function MyClass() {};
+  function MyClass() {}
   Object.defineProperty(MyClass, Symbol.hasInstance, {
     value: function(candidate) {
       return 'mark' in candidate;
     }
   });
 
-  const MySubClass = function MySubClass() {};
+  function MySubClass() {}
   MySubClass.prototype = new MyClass();
 
   let x = new MySubClass();
diff --git a/test/addons/make-callback/test.js b/test/addons/make-callback/test.js
index b67d1146a6..efea43df3c 100644
--- a/test/addons/make-callback/test.js
+++ b/test/addons/make-callback/test.js
@@ -57,9 +57,9 @@ const forward = vm.runInNewContext(`
     })
 `);
 // Runs in outer context.
-const endpoint = function($Object) {
+function endpoint($Object) {
   if (Object === $Object)
     throw new Error('bad');
   return Object;
-};
+}
 assert.strictEqual(Object, makeCallback(process, forward, endpoint));
diff --git a/test/inspector/inspector-helper.js b/test/inspector/inspector-helper.js
index 05dd773552..2fb6a0e999 100644
--- a/test/inspector/inspector-helper.js
+++ b/test/inspector/inspector-helper.js
@@ -122,7 +122,7 @@ function timeout(message, multiplicator) {
                     TIMEOUT * (multiplicator || 1));
 }
 
-const TestSession = function(socket, harness) {
+function TestSession(socket, harness) {
   this.mainScriptPath = harness.mainScriptPath;
   this.mainScriptId = null;
 
@@ -147,7 +147,7 @@ const TestSession = function(socket, harness) {
         buffer = buffer.slice(consumed);
     } while (consumed);
   }).on('close', () => assert(this.expectClose_, 'Socket closed prematurely'));
-};
+}
 
 TestSession.prototype.scriptUrlForId = function(id) {
   return this.scripts_[id];
@@ -304,7 +304,7 @@ TestSession.prototype.testHttpResponse = function(path, check) {
 };
 
 
-const Harness = function(port, childProcess) {
+function Harness(port, childProcess) {
   this.port = port;
   this.mainScriptPath = mainScript;
   this.stderrFilters_ = [];
@@ -329,7 +329,7 @@ const Harness = function(port, childProcess) {
     this.returnCode_ = code;
     this.running_ = false;
   });
-};
+}
 
 Harness.prototype.addStderrFilter = function(regexp, callback) {
   this.stderrFilters_.push((message) => {
diff --git a/test/parallel/test-assert.js b/test/parallel/test-assert.js
index 89a54df81a..568f23344e 100644
--- a/test/parallel/test-assert.js
+++ b/test/parallel/test-assert.js
@@ -449,7 +449,7 @@ a.throws(makeBlock(thrower, TypeError), function(err) {
 
     AnotherErrorType = class extends Error {};
 
-    const functionThatThrows = function() {
+    const functionThatThrows = () => {
       throw new AnotherErrorType('foo');
     };
 
@@ -493,6 +493,7 @@ a.throws(makeBlock(a.deepEqual, args, []));
 
 // more checking that arguments objects are handled correctly
 {
+  // eslint-disable-next-line func-style
   const returnArguments = function() { return arguments; };
 
   const someArgs = returnArguments('a');
diff --git a/test/parallel/test-child-process-fork-dgram.js b/test/parallel/test-child-process-fork-dgram.js
index 784e5e55f2..be351cced0 100644
--- a/test/parallel/test-child-process-fork-dgram.js
+++ b/test/parallel/test-child-process-fork-dgram.js
@@ -78,7 +78,7 @@ if (process.argv[2] === 'child') {
     });
   });
 
-  const sendMessages = function() {
+  function sendMessages() {
     const serverPort = parentServer.address().port;
 
     const timer = setInterval(function() {
@@ -102,7 +102,7 @@ if (process.argv[2] === 'child') {
         );
       }
     }, 1);
-  };
+  }
 
   parentServer.bind(0, '127.0.0.1');
 
diff --git a/test/parallel/test-child-process-fork-net.js b/test/parallel/test-child-process-fork-net.js
index 42994007e8..de0ec6ca00 100644
--- a/test/parallel/test-child-process-fork-net.js
+++ b/test/parallel/test-child-process-fork-net.js
@@ -87,7 +87,7 @@ if (process.argv[2] === 'child') {
   }));
 
   // send net.Server to child and test by connecting
-  const testServer = function(callback) {
+  function testServer(callback) {
 
     // destroy server execute callback when done
     const progress = new ProgressTracker(2, function() {
@@ -116,7 +116,7 @@ if (process.argv[2] === 'child') {
     server.listen(0);
 
     // handle client messages
-    const messageHandlers = function(msg) {
+    function messageHandlers(msg) {
 
       if (msg.what === 'listening') {
         // make connections
@@ -138,13 +138,13 @@ if (process.argv[2] === 'child') {
         child.removeListener('message', messageHandlers);
         callback();
       }
-    };
+    }
 
     child.on('message', messageHandlers);
-  };
+  }
 
   // send net.Socket to child
-  const testSocket = function(callback) {
+  function testSocket(callback) {
 
     // create a new server and connect to it,
     // but the socket will be handled by the child
@@ -179,7 +179,7 @@ if (process.argv[2] === 'child') {
         server.close();
       });
     });
-  };
+  }
 
   // create server and send it to child
   let serverSuccess = false;
diff --git a/test/parallel/test-child-process-fork-net2.js b/test/parallel/test-child-process-fork-net2.js
index 737720cd6a..b893685447 100644
--- a/test/parallel/test-child-process-fork-net2.js
+++ b/test/parallel/test-child-process-fork-net2.js
@@ -144,7 +144,7 @@ if (process.argv[2] === 'child') {
 
   server.listen(0, '127.0.0.1');
 
-  const closeServer = function() {
+  function closeServer() {
     server.close();
 
     setTimeout(function() {
@@ -153,7 +153,7 @@ if (process.argv[2] === 'child') {
       child2.send('close');
       child3.disconnect();
     }, 200);
-  };
+  }
 
   process.on('exit', function() {
     assert.strictEqual(disconnected, count);
diff --git a/test/parallel/test-child-process-spawn-typeerror.js b/test/parallel/test-child-process-spawn-typeerror.js
index 70a0ea443c..cf5884b38f 100644
--- a/test/parallel/test-child-process-spawn-typeerror.js
+++ b/test/parallel/test-child-process-spawn-typeerror.js
@@ -89,7 +89,7 @@ assert.throws(function() {
 // Argument types for combinatorics
 const a = [];
 const o = {};
-const c = function c() {};
+function c() {}
 const s = 'string';
 const u = undefined;
 const n = null;
diff --git a/test/parallel/test-cluster-disconnect.js b/test/parallel/test-cluster-disconnect.js
index 0f43b4ef59..2286ca1d67 100644
--- a/test/parallel/test-cluster-disconnect.js
+++ b/test/parallel/test-cluster-disconnect.js
@@ -38,7 +38,7 @@ if (cluster.isWorker) {
   const servers = 2;
 
   // test a single TCP server
-  const testConnection = function(port, cb) {
+  const testConnection = (port, cb) => {
     const socket = net.connect(port, '127.0.0.1', () => {
       // buffer result
       let result = '';
@@ -52,7 +52,7 @@ if (cluster.isWorker) {
   };
 
   // test both servers created in the cluster
-  const testCluster = function(cb) {
+  const testCluster = (cb) => {
     let done = 0;
 
     for (let i = 0; i < servers; i++) {
@@ -67,7 +67,7 @@ if (cluster.isWorker) {
   };
 
   // start two workers and execute callback when both is listening
-  const startCluster = function(cb) {
+  const startCluster = (cb) => {
     const workers = 8;
     let online = 0;
 
@@ -81,7 +81,7 @@ if (cluster.isWorker) {
     }
   };
 
-  const test = function(again) {
+  const test = (again) => {
     //1. start cluster
     startCluster(common.mustCall(() => {
       //2. test cluster
diff --git a/test/parallel/test-cluster-master-error.js b/test/parallel/test-cluster-master-error.js
index 0a2dcc43fa..cc104ec441 100644
--- a/test/parallel/test-cluster-master-error.js
+++ b/test/parallel/test-cluster-master-error.js
@@ -101,7 +101,7 @@ if (cluster.isWorker) {
     // Check that the cluster died accidentally (non-zero exit code)
     masterExited = !!code;
 
-    const pollWorkers = function() {
+    const pollWorkers = () => {
       // When master is dead all workers should be dead too
       let alive = false;
       workers.forEach((pid) => alive = common.isAlive(pid));
diff --git a/test/parallel/test-cluster-master-kill.js b/test/parallel/test-cluster-master-kill.js
index f195599b3f..f00dc48b71 100644
--- a/test/parallel/test-cluster-master-kill.js
+++ b/test/parallel/test-cluster-master-kill.js
@@ -68,7 +68,7 @@ if (cluster.isWorker) {
     assert.strictEqual(code, 0);
 
     // check worker process status
-    const pollWorker = function() {
+    const pollWorker = () => {
       alive = common.isAlive(pid);
       if (alive) {
         setTimeout(pollWorker, 50);
diff --git a/test/parallel/test-cluster-message.js b/test/parallel/test-cluster-message.js
index ee7100185a..df9f8ca2a4 100644
--- a/test/parallel/test-cluster-message.js
+++ b/test/parallel/test-cluster-message.js
@@ -80,7 +80,7 @@ if (cluster.isWorker) {
 
 
   let client;
-  const check = function(type, result) {
+  const check = (type, result) => {
     checks[type].receive = true;
     checks[type].correct = result;
     console.error('check', checks);
diff --git a/test/parallel/test-cluster-worker-exit.js b/test/parallel/test-cluster-worker-exit.js
index db8835abe4..18d6fe25eb 100644
--- a/test/parallel/test-cluster-worker-exit.js
+++ b/test/parallel/test-cluster-worker-exit.js
@@ -103,7 +103,7 @@ if (cluster.isWorker) {
     }
   }));
 
-  const finish_test = function() {
+  const finish_test = () => {
     try {
       checkResults(expected_results, results);
     } catch (exc) {
diff --git a/test/parallel/test-console-not-call-toString.js b/test/parallel/test-console-not-call-toString.js
index 3c2df00d47..0f6f2624c5 100644
--- a/test/parallel/test-console-not-call-toString.js
+++ b/test/parallel/test-console-not-call-toString.js
@@ -23,7 +23,7 @@
 require('../common');
 const assert = require('assert');
 
-const func = function() {};
+function func() {}
 let toStringCalled = false;
 func.toString = function() {
   toStringCalled = true;
diff --git a/test/parallel/test-event-emitter-add-listeners.js b/test/parallel/test-event-emitter-add-listeners.js
index a4bfcb3442..d6177a7880 100644
--- a/test/parallel/test-event-emitter-add-listeners.js
+++ b/test/parallel/test-event-emitter-add-listeners.js
@@ -68,8 +68,8 @@ const EventEmitter = require('events');
 }
 
 {
-  const listen1 = function listen1() {};
-  const listen2 = function listen2() {};
+  const listen1 = () => {};
+  const listen2 = () => {};
   const ee = new EventEmitter();
 
   ee.once('newListener', function() {
diff --git a/test/parallel/test-event-emitter-once.js b/test/parallel/test-event-emitter-once.js
index 8a7bbbf9bc..6823a9805e 100644
--- a/test/parallel/test-event-emitter-once.js
+++ b/test/parallel/test-event-emitter-once.js
@@ -33,9 +33,9 @@ e.emit('hello', 'a', 'b');
 e.emit('hello', 'a', 'b');
 e.emit('hello', 'a', 'b');
 
-const remove = function() {
+function remove() {
   assert.fail('once->foo should not be emitted');
-};
+}
 
 e.once('foo', remove);
 e.removeListener('foo', remove);
diff --git a/test/parallel/test-fs-access.js b/test/parallel/test-fs-access.js
index d5934dd614..f378824cbc 100644
--- a/test/parallel/test-fs-access.js
+++ b/test/parallel/test-fs-access.js
@@ -7,10 +7,10 @@ const doesNotExist = path.join(common.tmpDir, '__this_should_not_exist');
 const readOnlyFile = path.join(common.tmpDir, 'read_only_file');
 const readWriteFile = path.join(common.tmpDir, 'read_write_file');
 
-const createFileWithPerms = function(file, mode) {
+function createFileWithPerms(file, mode) {
   fs.writeFileSync(file, '');
   fs.chmodSync(file, mode);
-};
+}
 
 common.refreshTmpDir();
 createFileWithPerms(readOnlyFile, 0o444);
diff --git a/test/parallel/test-fs-link.js b/test/parallel/test-fs-link.js
index d110ff80fe..525392aa2b 100644
--- a/test/parallel/test-fs-link.js
+++ b/test/parallel/test-fs-link.js
@@ -11,11 +11,11 @@ const srcPath = path.join(common.tmpDir, 'hardlink-target.txt');
 const dstPath = path.join(common.tmpDir, 'link1.js');
 fs.writeFileSync(srcPath, 'hello world');
 
-const callback = function(err) {
+function callback(err) {
   assert.ifError(err);
   const dstContent = fs.readFileSync(dstPath, 'utf8');
   assert.strictEqual('hello world', dstContent);
-};
+}
 
 fs.link(srcPath, dstPath, common.mustCall(callback));
 
diff --git a/test/parallel/test-fs-read-stream-fd-leak.js b/test/parallel/test-fs-read-stream-fd-leak.js
index 0a7a42a3ba..e6594afefc 100644
--- a/test/parallel/test-fs-read-stream-fd-leak.js
+++ b/test/parallel/test-fs-read-stream-fd-leak.js
@@ -29,7 +29,7 @@ function testLeak(endFn, callback) {
   let i = 0;
   let check = 0;
 
-  const checkFunction = function() {
+  function checkFunction() {
     if (openCount !== 0 && check < totalCheck) {
       check++;
       setTimeout(checkFunction, 100);
@@ -44,7 +44,7 @@ function testLeak(endFn, callback) {
 
     openCount = 0;
     callback && setTimeout(callback, 100);
-  };
+  }
 
   setInterval(function() {
     const s = fs.createReadStream(emptyTxt);
diff --git a/test/parallel/test-http-parser.js b/test/parallel/test-http-parser.js
index a4e03ab4c3..b919891cbf 100644
--- a/test/parallel/test-http-parser.js
+++ b/test/parallel/test-http-parser.js
@@ -96,9 +96,9 @@ function expectBody(expected) {
       'GET /hello HTTP/1.1' + CRLF +
       CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(versionMajor, 1);
     assert.strictEqual(versionMinor, 1);
     assert.strictEqual(method, methods.indexOf('GET'));
@@ -137,9 +137,9 @@ function expectBody(expected) {
       CRLF +
       'pong');
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, undefined);
     assert.strictEqual(versionMajor, 1);
     assert.strictEqual(versionMinor, 1);
@@ -147,7 +147,7 @@ function expectBody(expected) {
     assert.strictEqual(statusMessage, 'OK');
   };
 
-  const onBody = function(buf, start, len) {
+  const onBody = (buf, start, len) => {
     const body = '' + buf.slice(start, start + len);
     assert.strictEqual(body, 'pong');
   };
@@ -167,9 +167,9 @@ function expectBody(expected) {
       'HTTP/1.0 200 Connection established' + CRLF +
       CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(versionMajor, 1);
     assert.strictEqual(versionMinor, 0);
     assert.strictEqual(method, undefined);
@@ -201,15 +201,15 @@ function expectBody(expected) {
 
   let seen_body = false;
 
-  const onHeaders = function(headers, url) {
+  const onHeaders = (headers, url) => {
     assert.ok(seen_body); // trailers should come after the body
     assert.deepStrictEqual(headers,
                            ['Vary', '*', 'Content-Type', 'text/plain']);
   };
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('POST'));
     assert.strictEqual(url || parser.url, '/it');
     assert.strictEqual(versionMajor, 1);
@@ -218,7 +218,7 @@ function expectBody(expected) {
     parser[kOnHeaders] = mustCall(onHeaders);
   };
 
-  const onBody = function(buf, start, len) {
+  const onBody = (buf, start, len) => {
     const body = '' + buf.slice(start, start + len);
     assert.strictEqual(body, 'ping');
     seen_body = true;
@@ -242,9 +242,9 @@ function expectBody(expected) {
       'X-Filler2:  42' + CRLF +
       CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('GET'));
     assert.strictEqual(versionMajor, 1);
     assert.strictEqual(versionMinor, 0);
@@ -272,9 +272,9 @@ function expectBody(expected) {
       lots_of_headers +
       CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('GET'));
     assert.strictEqual(url || parser.url, '/foo/bar/baz?quux=42#1337');
     assert.strictEqual(versionMajor, 1);
@@ -306,16 +306,16 @@ function expectBody(expected) {
       CRLF +
       'foo=42&bar=1337');
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('POST'));
     assert.strictEqual(url || parser.url, '/it');
     assert.strictEqual(versionMajor, 1);
     assert.strictEqual(versionMinor, 1);
   };
 
-  const onBody = function(buf, start, len) {
+  const onBody = (buf, start, len) => {
     const body = '' + buf.slice(start, start + len);
     assert.strictEqual(body, 'foo=42&bar=1337');
   };
@@ -344,9 +344,9 @@ function expectBody(expected) {
       '1234567890' + CRLF +
       '0' + CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('POST'));
     assert.strictEqual(url || parser.url, '/it');
     assert.strictEqual(versionMajor, 1);
@@ -356,7 +356,7 @@ function expectBody(expected) {
   let body_part = 0;
   const body_parts = ['123', '123456', '1234567890'];
 
-  const onBody = function(buf, start, len) {
+  const onBody = (buf, start, len) => {
     const body = '' + buf.slice(start, start + len);
     assert.strictEqual(body, body_parts[body_part++]);
   };
@@ -382,9 +382,9 @@ function expectBody(expected) {
       '6' + CRLF +
       '123456' + CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('POST'));
     assert.strictEqual(url || parser.url, '/it');
     assert.strictEqual(versionMajor, 1);
@@ -395,7 +395,7 @@ function expectBody(expected) {
   const body_parts =
           ['123', '123456', '123456789', '123456789ABC', '123456789ABCDEF'];
 
-  const onBody = function(buf, start, len) {
+  const onBody = (buf, start, len) => {
     const body = '' + buf.slice(start, start + len);
     assert.strictEqual(body, body_parts[body_part++]);
   };
@@ -440,9 +440,9 @@ function expectBody(expected) {
       '0' + CRLF);
 
   function test(a, b) {
-    const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                       method, url, statusCode, statusMessage,
-                                       upgrade, shouldKeepAlive) {
+    const onHeadersComplete = (versionMajor, versionMinor, headers,
+                               method, url, statusCode, statusMessage,
+                               upgrade, shouldKeepAlive) => {
       assert.strictEqual(method, methods.indexOf('POST'));
       assert.strictEqual(url || parser.url, '/helpme');
       assert.strictEqual(versionMajor, 1);
@@ -451,7 +451,7 @@ function expectBody(expected) {
 
     let expected_body = '123123456123456789123456789ABC123456789ABCDEF';
 
-    const onBody = function(buf, start, len) {
+    const onBody = (buf, start, len) => {
       const chunk = '' + buf.slice(start, start + len);
       assert.strictEqual(expected_body.indexOf(chunk), 0);
       expected_body = expected_body.slice(chunk.length);
@@ -499,9 +499,9 @@ function expectBody(expected) {
       '123456789ABCDEF' + CRLF +
       '0' + CRLF);
 
-  const onHeadersComplete = function(versionMajor, versionMinor, headers,
-                                     method, url, statusCode, statusMessage,
-                                     upgrade, shouldKeepAlive) {
+  const onHeadersComplete = (versionMajor, versionMinor, headers,
+                             method, url, statusCode, statusMessage,
+                             upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('POST'));
     assert.strictEqual(url || parser.url, '/it');
     assert.strictEqual(versionMajor, 1);
@@ -513,7 +513,7 @@ function expectBody(expected) {
 
   let expected_body = '123123456123456789123456789ABC123456789ABCDEF';
 
-  const onBody = function(buf, start, len) {
+  const onBody = (buf, start, len) => {
     const chunk = '' + buf.slice(start, start + len);
     assert.strictEqual(expected_body.indexOf(chunk), 0);
     expected_body = expected_body.slice(chunk.length);
@@ -551,9 +551,9 @@ function expectBody(expected) {
       CRLF +
       'pong');
 
-  const onHeadersComplete1 = function(versionMajor, versionMinor, headers,
-                                      method, url, statusCode, statusMessage,
-                                      upgrade, shouldKeepAlive) {
+  const onHeadersComplete1 = (versionMajor, versionMinor, headers,
+                              method, url, statusCode, statusMessage,
+                              upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('PUT'));
     assert.strictEqual(url, '/this');
     assert.strictEqual(versionMajor, 1);
@@ -563,9 +563,9 @@ function expectBody(expected) {
         ['Content-Type', 'text/plain', 'Transfer-Encoding', 'chunked']);
   };
 
-  const onHeadersComplete2 = function(versionMajor, versionMinor, headers,
-                                      method, url, statusCode, statusMessage,
-                                      upgrade, shouldKeepAlive) {
+  const onHeadersComplete2 = (versionMajor, versionMinor, headers,
+                              method, url, statusCode, statusMessage,
+                              upgrade, shouldKeepAlive) => {
     assert.strictEqual(method, methods.indexOf('POST'));
     assert.strictEqual(url, '/that');
     assert.strictEqual(versionMajor, 1);
diff --git a/test/parallel/test-http-response-status-message.js b/test/parallel/test-http-response-status-message.js
index ca0618caf0..b618de7559 100644
--- a/test/parallel/test-http-response-status-message.js
+++ b/test/parallel/test-http-response-status-message.js
@@ -59,7 +59,7 @@ const server = net.createServer(function(connection) {
   });
 });
 
-const runTest = function(testCaseIndex) {
+function runTest(testCaseIndex) {
   const testCase = testCases[testCaseIndex];
 
   http.get({
@@ -82,7 +82,7 @@ const runTest = function(testCaseIndex) {
 
     response.resume();
   });
-};
+}
 
 server.listen(0, function() { runTest(0); });
 
diff --git a/test/parallel/test-https-simple.js b/test/parallel/test-https-simple.js
index cb5a8d4146..d20f6bb205 100644
--- a/test/parallel/test-https-simple.js
+++ b/test/parallel/test-https-simple.js
@@ -39,7 +39,7 @@ const options = {
 const tests = 2;
 let successful = 0;
 
-const testSucceeded = function() {
+const testSucceeded = () => {
   successful = successful + 1;
   if (successful === tests) {
     server.close();
diff --git a/test/parallel/test-net-server-max-connections-close-makes-more-available.js b/test/parallel/test-net-server-max-connections-close-makes-more-available.js
index 887beb21d2..9fd34a6f45 100644
--- a/test/parallel/test-net-server-max-connections-close-makes-more-available.js
+++ b/test/parallel/test-net-server-max-connections-close-makes-more-available.js
@@ -17,7 +17,7 @@ const connections = [];
 const received = [];
 const sent = [];
 
-const createConnection = function(index) {
+function createConnection(index) {
   console.error('creating connection ' + index);
 
   return new Promise(function(resolve, reject) {
@@ -45,9 +45,9 @@ const createConnection = function(index) {
 
     connections[index] = connection;
   });
-};
+}
 
-const closeConnection = function(index) {
+function closeConnection(index) {
   console.error('closing connection ' + index);
   return new Promise(function(resolve, reject) {
     connections[index].on('end', function() {
@@ -55,7 +55,7 @@ const closeConnection = function(index) {
     });
     connections[index].end();
   });
-};
+}
 
 const server = net.createServer(function(socket) {
   socket.on('data', function(data) {
diff --git a/test/parallel/test-net-server-pause-on-connect.js b/test/parallel/test-net-server-pause-on-connect.js
index 6041de9970..e015c24323 100644
--- a/test/parallel/test-net-server-pause-on-connect.js
+++ b/test/parallel/test-net-server-pause-on-connect.js
@@ -28,7 +28,7 @@ let stopped = true;
 let server1Sock;
 
 
-const server1ConnHandler = function(socket) {
+const server1ConnHandler = (socket) => {
   socket.on('data', function(data) {
     if (stopped) {
       assert.fail('data event should not have happened yet');
@@ -44,7 +44,7 @@ const server1ConnHandler = function(socket) {
 
 const server1 = net.createServer({pauseOnConnect: true}, server1ConnHandler);
 
-const server2ConnHandler = function(socket) {
+const server2ConnHandler = (socket) => {
   socket.on('data', function(data) {
     assert.strictEqual(data.toString(), msg, 'invalid data received');
     socket.end();
diff --git a/test/parallel/test-os.js b/test/parallel/test-os.js
index 848e7963b2..6092c411a8 100644
--- a/test/parallel/test-os.js
+++ b/test/parallel/test-os.js
@@ -116,7 +116,7 @@ const interfaces = os.networkInterfaces();
 switch (platform) {
   case 'linux':
     {
-      const filter = function(e) { return e.address === '127.0.0.1'; };
+      const filter = (e) => e.address === '127.0.0.1';
       const actual = interfaces.lo.filter(filter);
       const expected = [{ address: '127.0.0.1', netmask: '255.0.0.0',
                           mac: '00:00:00:00:00:00', family: 'IPv4',
@@ -126,7 +126,7 @@ switch (platform) {
     }
   case 'win32':
     {
-      const filter = function(e) { return e.address === '127.0.0.1'; };
+      const filter = (e) => e.address === '127.0.0.1';
       const actual = interfaces['Loopback Pseudo-Interface 1'].filter(filter);
       const expected = [{ address: '127.0.0.1', netmask: '255.0.0.0',
                           mac: '00:00:00:00:00:00', family: 'IPv4',
diff --git a/test/parallel/test-preload.js b/test/parallel/test-preload.js
index 5d618e169e..17aef54290 100644
--- a/test/parallel/test-preload.js
+++ b/test/parallel/test-preload.js
@@ -13,7 +13,7 @@ if (common.isSunOS) {
 
 const nodeBinary = process.argv[0];
 
-const preloadOption = function(preloads) {
+const preloadOption = (preloads) => {
   let option = '';
   preloads.forEach(function(preload, index) {
     option += '-r ' + preload + ' ';
@@ -21,9 +21,7 @@ const preloadOption = function(preloads) {
   return option;
 };
 
-const fixture = function(name) {
-  return path.join(common.fixturesDir, name);
-};
+const fixture = (name) => path.join(common.fixturesDir, name);
 
 const fixtureA = fixture('printA.js');
 const fixtureB = fixture('printB.js');
diff --git a/test/parallel/test-querystring.js b/test/parallel/test-querystring.js
index 6d8dd2a7f2..0e5cfef362 100644
--- a/test/parallel/test-querystring.js
+++ b/test/parallel/test-querystring.js
@@ -107,7 +107,7 @@ const qsColonTestCases = [
 ];
 
 // [wonkyObj, qs, canonicalObj]
-const extendedFunction = function() {};
+function extendedFunction() {}
 extendedFunction.prototype = {a: 'b'};
 const qsWeirdObjects = [
   // eslint-disable-next-line no-unescaped-regexp-dot
diff --git a/test/parallel/test-readline-interface.js b/test/parallel/test-readline-interface.js
index f7c66c90c5..50a6bf2daa 100644
--- a/test/parallel/test-readline-interface.js
+++ b/test/parallel/test-readline-interface.js
@@ -288,9 +288,7 @@ function isWarned(emitter) {
 
   // \t does not become part of the input when there is a completer function
   fi = new FakeInput();
-  const completer = function(line) {
-    return [[], line];
-  };
+  const completer = (line) => [[], line];
   rli = new readline.Interface({
     input: fi,
     output: fi,
diff --git a/test/parallel/test-stream2-pipe-error-once-listener.js b/test/parallel/test-stream2-pipe-error-once-listener.js
index 078c3d935f..de65c2469e 100644
--- a/test/parallel/test-stream2-pipe-error-once-listener.js
+++ b/test/parallel/test-stream2-pipe-error-once-listener.js
@@ -26,9 +26,9 @@ const util = require('util');
 const stream = require('stream');
 
 
-const Read = function() {
+function Read() {
   stream.Readable.call(this);
-};
+}
 util.inherits(Read, stream.Readable);
 
 Read.prototype._read = function(size) {
@@ -37,9 +37,9 @@ Read.prototype._read = function(size) {
 };
 
 
-const Write = function() {
+function Write() {
   stream.Writable.call(this);
-};
+}
 util.inherits(Write, stream.Writable);
 
 Write.prototype._write = function(buffer, encoding, cb) {
diff --git a/test/parallel/test-timers-ordering.js b/test/parallel/test-timers-ordering.js
index 8a807f94cd..b3388cc9be 100644
--- a/test/parallel/test-timers-ordering.js
+++ b/test/parallel/test-timers-ordering.js
@@ -29,7 +29,7 @@ const N = 30;
 let last_i = 0;
 let last_ts = 0;
 
-const f = function(i) {
+function f(i) {
   if (i <= N) {
     // check order
     assert.strictEqual(i, last_i + 1, 'order is broken: ' + i + ' != ' +
@@ -46,5 +46,5 @@ const f = function(i) {
     // schedule next iteration
     setTimeout(f, 1, i + 1);
   }
-};
+}
 f(1);
diff --git a/test/parallel/test-util-inspect.js b/test/parallel/test-util-inspect.js
index 0b58af4080..d44bb8b870 100644
--- a/test/parallel/test-util-inspect.js
+++ b/test/parallel/test-util-inspect.js
@@ -296,7 +296,7 @@ assert.strictEqual(
 
 // Function with properties
 {
-  const value = function() {};
+  const value = () => {};
   value.aprop = 42;
   assert.strictEqual(util.inspect(value), '{ [Function: value] aprop: 42 }');
 }
diff --git a/test/pummel/test-dtrace-jsstack.js b/test/pummel/test-dtrace-jsstack.js
index b580984075..2c8611d11d 100644
--- a/test/pummel/test-dtrace-jsstack.js
+++ b/test/pummel/test-dtrace-jsstack.js
@@ -34,18 +34,18 @@ if (!common.isSunOS) {
  */
 const frames = [ 'stalloogle', 'bagnoogle', 'doogle' ];
 
-const stalloogle = function(str) {
+const stalloogle = (str) => {
   global.expected = str;
   os.loadavg();
 };
 
-const bagnoogle = function(arg0, arg1) {
+const bagnoogle = (arg0, arg1) => {
   stalloogle(arg0 + ' is ' + arg1 + ' except that it is read-only');
 };
 
 let done = false;
 
-const doogle = function() {
+const doogle = () => {
   if (!done)
     setTimeout(doogle, 10);
 
diff --git a/test/pummel/test-tls-session-timeout.js b/test/pummel/test-tls-session-timeout.js
index 23b79e312f..5807ae8a94 100644
--- a/test/pummel/test-tls-session-timeout.js
+++ b/test/pummel/test-tls-session-timeout.js
@@ -78,7 +78,7 @@ function doTest() {
 
   // Expects a callback -- cb(connectionType : enum ['New'|'Reused'])
 
-  const Client = function(cb) {
+  function Client(cb) {
     const flags = [
       's_client',
       '-connect', 'localhost:' + common.PORT,
@@ -95,7 +95,7 @@ function doTest() {
     });
     client.on('exit', function(code) {
       let connectionType;
-      const grepConnectionType = function(line) {
+      const grepConnectionType = (line) => {
         const matches = line.match(/(New|Reused), /);
         if (matches) {
           connectionType = matches[1];
@@ -108,7 +108,7 @@ function doTest() {
       }
       cb(connectionType);
     });
-  };
+  }
 
   const server = tls.createServer(options, function(cleartext) {
     cleartext.on('error', function(er) {