doc, lib, test: do not re-require needlessly

Backport-PR-URL: #14524
Backport-Reviewed-By: Anna Henningsen <anna@addaleax.net>

PR-URL: #14244
Reviewed-By: Alexey Orlenko <eaglexrlnk@gmail.com>

doc/api/child_process.md

@@ -1136,8 +1136,9 @@ 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('child.js', ['normal']);
-const special = require('child_process').fork('child.js', ['special']);
+const { fork } = require('child_process');
+const normal = fork('child.js', ['normal']);
+const special = fork('child.js', ['special']);
 
 // Open up the server and send sockets to child. Use pauseOnConnect to prevent
 // the sockets from being read before they are sent to the child process.

lib/_tls_legacy.js

@@ -21,14 +21,14 @@
 
 'use strict';
 
-require('internal/util').assertCrypto();
+const internalUtil = require('internal/util');
+internalUtil.assertCrypto();
 
 const assert = require('assert');
 const Buffer = require('buffer').Buffer;
 const common = require('_tls_common');
 const Connection = process.binding('crypto').Connection;
 const EventEmitter = require('events');
-const internalUtil = require('internal/util');
 const stream = require('stream');
 const Timer = process.binding('timer_wrap').Timer;
 const tls = require('tls');

lib/internal/process.js

@@ -1,5 +1,7 @@
 'use strict';
 
+const util = require('util');
+
 var _lazyConstants = null;
 
 function lazyConstants() {
@@ -178,10 +180,8 @@ function setupKillAndExit() {
       }
     }
 
-    if (err) {
-      const errnoException = require('util')._errnoException;
-      throw errnoException(err, 'kill');
-    }
+    if (err)
+      throw util._errnoException(err, 'kill');
 
     return true;
   };
@@ -212,8 +212,7 @@ 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;
@@ -253,10 +252,9 @@ 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

@@ -85,7 +85,7 @@ 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.

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

@@ -22,7 +22,7 @@
 'use strict';
 const common = 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

@@ -22,8 +22,7 @@
 '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-crypto-random.js

@@ -148,6 +148,8 @@ const expectedErrorRegexp = /^TypeError: size must be a number >= 0$/;
     bufferTooSmall: /^RangeError: buffer too small$/,
   };
 
+  const max = require('buffer').kMaxLength + 1;
+
   for (const buf of bufs) {
     const len = Buffer.byteLength(buf);
     assert.strictEqual(len, 10, `Expected byteLength of 10, got ${len}`);
@@ -168,8 +170,6 @@ const expectedErrorRegexp = /^TypeError: size must be a number >= 0$/;
       crypto.randomFill(buf, NaN, common.mustNotCall());
     }, errMessages.offsetNotNumber);
 
-    const max = require('buffer').kMaxLength + 1;
-
     assert.throws(() => {
       crypto.randomFillSync(buf, 11);
     }, errMessages.offsetOutOfRange);

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

@@ -20,7 +20,6 @@
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 'use strict';
-require('../common');
 const common = require('../common');
 const assert = require('assert');
 const domain = require('domain');

test/parallel/test-handle-wrap-isrefed.js

@@ -24,9 +24,10 @@ const strictEqual = require('assert').strictEqual;
 }
 
 
+const dgram = require('dgram');
+
 // dgram ipv4
 {
-  const dgram = require('dgram');
   const sock4 = dgram.createSocket('udp4');
   strictEqual(Object.getPrototypeOf(sock4._handle).hasOwnProperty('hasRef'),
               true, 'udp_wrap: ipv4: hasRef() missing');
@@ -46,7 +47,6 @@ const strictEqual = require('assert').strictEqual;
 
 // dgram ipv6
 {
-  const dgram = require('dgram');
   const sock6 = dgram.createSocket('udp6');
   strictEqual(Object.getPrototypeOf(sock6._handle).hasOwnProperty('hasRef'),
               true, 'udp_wrap: ipv6: hasRef() missing');

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

@@ -85,7 +85,6 @@ 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

@@ -40,35 +40,35 @@ 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

@@ -83,22 +83,23 @@ 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

@@ -27,8 +27,7 @@ const readline = require('readline');
 const internalReadline = require('internal/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');
 const util = require('util');
 
 common.refreshTmpDir();

test/parallel/test-stream2-push.js

@@ -21,9 +21,8 @@
 
 'use strict';
 require('../common');
-const Readable = require('stream').Readable;
-const Writable = require('stream').Writable;
 const assert = require('assert');
+const { Readable, Writable } = require('stream');
 
 const EE = require('events').EventEmitter;
 

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

@@ -28,6 +28,15 @@ 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() {
     doTest({ tickets: false, invalidSession: true }, function() {
@@ -37,14 +46,6 @@ doTest({ tickets: false }, function() {
 });
 
 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 = {