[v6.x backport] doc, lib, test: do not re-require needlessly

doc/api/child_process.md

@@ -1046,8 +1046,9 @@ socket to the child process. The example below spawns two children that each
 handle connections with "normal" or "special" priority:
 
 ```js
-const normal = require('child_process').fork('subprocess.js', ['normal']);
-const special = require('child_process').fork('subprocess.js', ['special']);
+const { fork } = require('child_process');
+const normal = fork('subprocess.js', ['normal']);
+const special = fork('subprocess.js', ['special']);
 
 // Open up the server and send sockets to child
 const server = require('net').createServer();

lib/internal/process.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const util = require('util');
+
 var _lazyConstants = null;
 
 function lazyConstants() {
@@ -185,10 +187,8 @@ function setupKillAndExit() {
       }
     }
 
-    if (err) {
-      const errnoException = require('util')._errnoException;
-      throw errnoException(err, 'kill');
-    }
+    if (err)
+      throw util._errnoException(err, 'kill');
 
     return true;
   };
@@ -220,8 +220,7 @@ function setupSignalHandlers() {
       const err = wrap.start(signum);
       if (err) {
         wrap.close();
-        const errnoException = require('util')._errnoException;
-        throw errnoException(err, 'uv_signal_start');
+        throw util._errnoException(err, 'uv_signal_start');
       }
 
       signalWraps[type] = wrap;
@@ -261,9 +260,8 @@ function setupChannel() {
 
 
 function setupRawDebug() {
-  const format = require('util').format;
   const rawDebug = process._rawDebug;
   process._rawDebug = function() {
-    rawDebug(format.apply(null, arguments));
+    rawDebug(util.format.apply(null, arguments));
   };
 }

lib/repl.js

@@ -61,7 +61,7 @@ try {
 }
 
 // hack for repl require to work properly with node_modules folders
-module.paths = require('module')._nodeModulePaths(module.filename);
+module.paths = Module._nodeModulePaths(module.filename);
 
 // If obj.hasOwnProperty has been overridden, then calling
 // obj.hasOwnProperty(prop) will break.
@@ -869,7 +869,7 @@ function complete(line, callback) {
     filter = match[1];
     var dir, files, f, name, base, ext, abs, subfiles, s;
     group = [];
-    var paths = module.paths.concat(require('module').globalPaths);
+    var paths = module.paths.concat(Module.globalPaths);
     for (i = 0; i < paths.length; i++) {
       dir = path.resolve(paths[i], subdir);
       try {

test/common/index.js

@@ -4,7 +4,7 @@ const path = require('path');
 const fs = require('fs');
 const assert = require('assert');
 const os = require('os');
-const child_process = require('child_process');
+const { exec, execSync, spawn, spawnSync } = require('child_process');
 const stream = require('stream');
 const util = require('util');
 const Timer = process.binding('timer_wrap').Timer;
@@ -121,7 +121,7 @@ Object.defineProperty(exports, 'inFreeBSDJail', {
     if (inFreeBSDJail !== null) return inFreeBSDJail;
 
     if (exports.isFreeBSD &&
-      child_process.execSync('sysctl -n security.jail.jailed').toString() ===
+      execSync('sysctl -n security.jail.jailed').toString() ===
       '1\n') {
       inFreeBSDJail = true;
     } else {
@@ -168,7 +168,7 @@ Object.defineProperty(exports, 'opensslCli', {get: function() {
 
   if (exports.isWindows) opensslCli += '.exe';
 
-  const opensslCmd = child_process.spawnSync(opensslCli, ['version']);
+  const opensslCmd = spawnSync(opensslCli, ['version']);
   if (opensslCmd.status !== 0 || opensslCmd.error !== undefined) {
     // openssl command cannot be executed
     opensslCli = false;
@@ -219,7 +219,7 @@ exports.childShouldThrowAndAbort = function() {
   }
   testCmd += `"${process.argv[0]}" --abort-on-uncaught-exception `;
   testCmd += `"${process.argv[1]}" child`;
-  const child = child_process.exec(testCmd);
+  const child = exec(testCmd);
   child.on('exit', function onExit(exitCode, signal) {
     const errMsg = 'Test should have aborted ' +
                    `but instead exited with exit code ${exitCode}` +
@@ -239,8 +239,6 @@ exports.ddCommand = function(filename, kilobytes) {
 
 
 exports.spawnCat = function(options) {
-  const spawn = require('child_process').spawn;
-
   if (exports.isWindows) {
     return spawn('more', [], options);
   } else {
@@ -250,8 +248,6 @@ exports.spawnCat = function(options) {
 
 
 exports.spawnSyncCat = function(options) {
-  const spawnSync = require('child_process').spawnSync;
-
   if (exports.isWindows) {
     return spawnSync('more', [], options);
   } else {
@@ -261,8 +257,6 @@ exports.spawnSyncCat = function(options) {
 
 
 exports.spawnPwd = function(options) {
-  const spawn = require('child_process').spawn;
-
   if (exports.isWindows) {
     return spawn('cmd.exe', ['/c', 'cd'], options);
   } else {
@@ -272,8 +266,6 @@ exports.spawnPwd = function(options) {
 
 
 exports.spawnSyncPwd = function(options) {
-  const spawnSync = require('child_process').spawnSync;
-
   if (exports.isWindows) {
     return spawnSync('cmd.exe', ['/c', 'cd'], options);
   } else {

test/parallel/test-assert-typedarray-deepequal.js

@@ -2,7 +2,6 @@
 
 require('../common');
 const assert = require('assert');
-const a = require('assert');
 
 function makeBlock(f) {
   const args = Array.prototype.slice.call(arguments, 1);
@@ -51,7 +50,8 @@ equalArrayPairs.forEach((arrayPair) => {
 
 notEqualArrayPairs.forEach((arrayPair) => {
   assert.throws(
-    makeBlock(a.deepEqual, arrayPair[0], arrayPair[1]),
-    a.AssertionError
+    // eslint-disable-next-line no-restricted-properties
+    makeBlock(assert.deepEqual, arrayPair[0], arrayPair[1]),
+    assert.AssertionError
   );
 });

test/parallel/test-assert.js

@@ -1,7 +1,7 @@
 'use strict';
 require('../common');
 const assert = require('assert');
-const a = require('assert');
+const a = assert;
 
 function makeBlock(f) {
   const args = Array.prototype.slice.call(arguments, 1);

test/parallel/test-child-process-fork-and-spawn.js

@@ -1,8 +1,7 @@
 'use strict';
 const common = require('../common');
 const assert = require('assert');
-const spawn = require('child_process').spawn;
-const fork = require('child_process').fork;
+const { fork, spawn } = require('child_process');
 
 // Fork, then spawn. The spawned process should not hang.
 switch (process.argv[2] || '') {

test/parallel/test-child-process-send-returns-boolean.js

@@ -3,8 +3,7 @@ const common = require('../common');
 const assert = require('assert');
 const path = require('path');
 const net = require('net');
-const fork = require('child_process').fork;
-const spawn = require('child_process').spawn;
+const { fork, spawn } = require('child_process');
 
 const emptyFile = path.join(common.fixturesDir, 'empty.js');
 

test/parallel/test-domain-exit-dispose.js

@@ -1,5 +1,4 @@
 'use strict';
-require('../common');
 const common = require('../common');
 const assert = require('assert');
 const domain = require('domain');

test/parallel/test-http-invalidheaderfield2.js

@@ -2,8 +2,7 @@
 require('../common');
 const assert = require('assert');
 const inspect = require('util').inspect;
-const checkIsHttpToken = require('_http_common')._checkIsHttpToken;
-const checkInvalidHeaderChar = require('_http_common')._checkInvalidHeaderChar;
+const { _checkIsHttpToken, _checkInvalidHeaderChar } = require('_http_common');
 
 // Good header field names
 [
@@ -29,8 +28,8 @@ const checkInvalidHeaderChar = require('_http_common')._checkInvalidHeaderChar;
   '3.14159265359'
 ].forEach(function(str) {
   assert.strictEqual(
-    checkIsHttpToken(str), true,
-    `checkIsHttpToken(${inspect(str)}) unexpectedly failed`);
+    _checkIsHttpToken(str), true,
+    `_checkIsHttpToken(${inspect(str)}) unexpectedly failed`);
 });
 // Bad header field names
 [
@@ -55,8 +54,8 @@ const checkInvalidHeaderChar = require('_http_common')._checkInvalidHeaderChar;
   'This,That'
 ].forEach(function(str) {
   assert.strictEqual(
-    checkIsHttpToken(str), false,
-    `checkIsHttpToken(${inspect(str)}) unexpectedly succeeded`);
+    _checkIsHttpToken(str), false,
+    `_checkIsHttpToken(${inspect(str)}) unexpectedly succeeded`);
 });
 
 
@@ -68,8 +67,8 @@ const checkInvalidHeaderChar = require('_http_common')._checkInvalidHeaderChar;
   '!@#$%^&*()-_=+\\;\':"[]{}<>,./?|~`'
 ].forEach(function(str) {
   assert.strictEqual(
-    checkInvalidHeaderChar(str), false,
-    `checkInvalidHeaderChar(${inspect(str)}) unexpectedly failed`);
+    _checkInvalidHeaderChar(str), false,
+    `_checkInvalidHeaderChar(${inspect(str)}) unexpectedly failed`);
 });
 
 // Bad header field values
@@ -84,6 +83,6 @@ const checkInvalidHeaderChar = require('_http_common')._checkInvalidHeaderChar;
   'Ding!\x07'
 ].forEach(function(str) {
   assert.strictEqual(
-    checkInvalidHeaderChar(str), true,
-    `checkInvalidHeaderChar(${inspect(str)}) unexpectedly succeeded`);
+    _checkInvalidHeaderChar(str), true,
+    `_checkInvalidHeaderChar(${inspect(str)}) unexpectedly succeeded`);
 });

test/parallel/test-listen-fd-detached.js

@@ -64,7 +64,6 @@ function parent() {
   }).listen(0, function() {
     console.error('server listening on %d', this.address().port);
 
-    const spawn = require('child_process').spawn;
     const child = spawn(process.execPath, [__filename, 'child'], {
       stdio: [ 'ignore', 'ignore', 'ignore', server._handle ],
       detached: true

test/parallel/test-net-pause-resume-connecting.js

@@ -19,35 +19,35 @@ const server = net.createServer(function(conn) {
 
 server.listen(0, function() {
   // Client 1
-  conn = require('net').createConnection(this.address().port, 'localhost');
+  conn = net.createConnection(this.address().port, 'localhost');
   conn.resume();
   conn.on('data', onDataOk);
 
 
   // Client 2
-  conn = require('net').createConnection(this.address().port, 'localhost');
+  conn = net.createConnection(this.address().port, 'localhost');
   conn.pause();
   conn.resume();
   conn.on('data', onDataOk);
 
 
   // Client 3
-  conn = require('net').createConnection(this.address().port, 'localhost');
+  conn = net.createConnection(this.address().port, 'localhost');
   conn.pause();
   conn.on('data', common.mustNotCall());
   scheduleTearDown(conn);
 
 
   // Client 4
-  conn = require('net').createConnection(this.address().port, 'localhost');
+  conn = net.createConnection(this.address().port, 'localhost');
   conn.resume();
   conn.pause();
   conn.resume();
   conn.on('data', onDataOk);
 
 
   // Client 5
-  conn = require('net').createConnection(this.address().port, 'localhost');
+  conn = net.createConnection(this.address().port, 'localhost');
   conn.resume();
   conn.resume();
   conn.pause();

test/parallel/test-process-exit-code.js

@@ -62,22 +62,23 @@ function child5() {
 }
 
 function parent() {
+  const { spawn } = require('child_process');
+  const node = process.execPath;
+  const f = __filename;
+  const option = { stdio: [ 0, 1, 'ignore' ] };
+
+  const test = (arg, exit) => {
+    spawn(node, [f, arg], option).on('exit', (code) => {
+      assert.strictEqual(
+        code, exit,
+        `wrong exit for ${arg}\nexpected:${exit} but got:${code}`);
+      console.log('ok - %s exited with %d', arg, exit);
+    });
+  };
+
   test('child1', 42);
   test('child2', 42);
   test('child3', 0);
   test('child4', 1);
   test('child5', 99);
 }
-
-function test(arg, exit) {
-  const spawn = require('child_process').spawn;
-  const node = process.execPath;
-  const f = __filename;
-  const option = { stdio: [ 0, 1, 'ignore' ] };
-  spawn(node, [f, arg], option).on('exit', function(code) {
-    assert.strictEqual(
-      code, exit,
-      `wrong exit for ${arg}\nexpected:${exit} but got:${code}`);
-    console.log('ok - %s exited with %d', arg, exit);
-  });
-}

test/parallel/test-readline-interface.js

@@ -4,8 +4,7 @@ const assert = require('assert');
 const readline = require('readline');
 const EventEmitter = require('events').EventEmitter;
 const inherits = require('util').inherits;
-const Writable = require('stream').Writable;
-const Readable = require('stream').Readable;
+const { Writable, Readable } = require('stream');
 
 function FakeInput() {
   EventEmitter.call(this);

test/parallel/test-require-symlink.js

@@ -4,8 +4,7 @@ const common = require('../common');
 const assert = require('assert');
 const path = require('path');
 const fs = require('fs');
-const exec = require('child_process').exec;
-const spawn = require('child_process').spawn;
+const { exec, spawn } = require('child_process');
 
 common.refreshTmpDir();
 

test/parallel/test-tls-session-cache.js

@@ -7,21 +7,22 @@ if (!common.opensslCli)
 if (!common.hasCrypto)
   common.skip('missing crypto');
 
+const assert = require('assert');
+const tls = require('tls');
+const fs = require('fs');
+const { join } = require('path');
+const { spawn } = require('child_process');
+
+const keyFile = join(common.fixturesDir, 'agent.key');
+const certFile = join(common.fixturesDir, 'agent.crt');
+
 doTest({ tickets: false }, function() {
   doTest({ tickets: true }, function() {
     console.error('all done');
   });
 });
 
 function doTest(testOptions, callback) {
-  const assert = require('assert');
-  const tls = require('tls');
-  const fs = require('fs');
-  const join = require('path').join;
-  const spawn = require('child_process').spawn;
-
-  const keyFile = join(common.fixturesDir, 'agent.key');
-  const certFile = join(common.fixturesDir, 'agent.crt');
   const key = fs.readFileSync(keyFile);
   const cert = fs.readFileSync(certFile);
   const options = {