lib: use destructuring for some constants

This change is to unify the declaration for constants into using
destructuring on the top-level-module scope, reducing some redundant
code.

PR-URL: #16063
Backport-PR-URL: #16494
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Tobias Nießen <tniessen@tnie.de>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Gibson Fahnestock <gibfahn@gmail.com>

lib/_http_agent.js

@@ -25,8 +25,8 @@ const net = require('net');
 const util = require('util');
 const EventEmitter = require('events');
 const debug = util.debuglog('http');
-const async_id_symbol = process.binding('async_wrap').async_id_symbol;
-const nextTick = require('internal/process/next_tick').nextTick;
+const { async_id_symbol } = process.binding('async_wrap');
+const { nextTick } = require('internal/process/next_tick');
 
 // New Agent code.
 

lib/_http_client.js

@@ -24,19 +24,21 @@
 const util = require('util');
 const net = require('net');
 const url = require('url');
-const HTTPParser = process.binding('http_parser').HTTPParser;
+const { HTTPParser } = process.binding('http_parser');
 const assert = require('assert').ok;
-const common = require('_http_common');
-const httpSocketSetup = common.httpSocketSetup;
-const parsers = common.parsers;
-const freeParser = common.freeParser;
-const debug = common.debug;
-const OutgoingMessage = require('_http_outgoing').OutgoingMessage;
+const {
+  _checkIsHttpToken: checkIsHttpToken,
+  debug,
+  freeParser,
+  httpSocketSetup,
+  parsers
+} = require('_http_common');
+const { OutgoingMessage } = require('_http_outgoing');
 const Agent = require('_http_agent');
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const { urlToOptions, searchParamsSymbol } = require('internal/url');
-const outHeadersKey = require('internal/http').outHeadersKey;
-const nextTick = require('internal/process/next_tick').nextTick;
+const { outHeadersKey } = require('internal/http');
+const { nextTick } = require('internal/process/next_tick');
 
 // The actual list of disallowed characters in regexp form is more like:
 //    /[^A-Za-z0-9\-._~!$&'()*+,;=/:@]/
@@ -149,7 +151,7 @@ function ClientRequest(options, cb) {
   }
 
   if (methodIsString && method) {
-    if (!common._checkIsHttpToken(method)) {
+    if (!checkIsHttpToken(method)) {
       throw new TypeError('Method must be a valid HTTP token');
     }
     method = this.method = method.toUpperCase();

lib/_http_common.js

@@ -22,16 +22,17 @@
 'use strict';
 
 const binding = process.binding('http_parser');
-const methods = binding.methods;
-const HTTPParser = binding.HTTPParser;
+const { methods, HTTPParser } = binding;
 
 const FreeList = require('internal/freelist');
-const ondrain = require('internal/http').ondrain;
+const { ondrain } = require('internal/http');
 const incoming = require('_http_incoming');
-const emitDestroy = require('async_hooks').emitDestroy;
-const IncomingMessage = incoming.IncomingMessage;
-const readStart = incoming.readStart;
-const readStop = incoming.readStop;
+const { emitDestroy } = require('async_hooks');
+const {
+  IncomingMessage,
+  readStart,
+  readStop
+} = incoming;
 
 const debug = require('util').debuglog('http');
 

lib/_http_outgoing.js

@@ -26,17 +26,16 @@ const Stream = require('stream');
 const util = require('util');
 const internalUtil = require('internal/util');
 const internalHttp = require('internal/http');
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const common = require('_http_common');
 const checkIsHttpToken = common._checkIsHttpToken;
 const checkInvalidHeaderChar = common._checkInvalidHeaderChar;
-const outHeadersKey = require('internal/http').outHeadersKey;
-const async_id_symbol = process.binding('async_wrap').async_id_symbol;
-const nextTick = require('internal/process/next_tick').nextTick;
+const { outHeadersKey } = require('internal/http');
+const { async_id_symbol } = process.binding('async_wrap');
+const { nextTick } = require('internal/process/next_tick');
 
-const CRLF = common.CRLF;
-const debug = common.debug;
-const utcDate = internalHttp.utcDate;
+const { CRLF, debug } = common;
+const { utcDate } = internalHttp;
 
 var RE_FIELDS =
   /^(?:Connection|Transfer-Encoding|Content-Length|Date|Expect|Trailer|Upgrade)$/i;

lib/_http_server.js

@@ -23,17 +23,19 @@
 
 const util = require('util');
 const net = require('net');
-const HTTPParser = process.binding('http_parser').HTTPParser;
+const { HTTPParser } = process.binding('http_parser');
 const assert = require('assert').ok;
-const common = require('_http_common');
-const parsers = common.parsers;
-const freeParser = common.freeParser;
-const debug = common.debug;
-const CRLF = common.CRLF;
-const continueExpression = common.continueExpression;
-const chunkExpression = common.chunkExpression;
-const httpSocketSetup = common.httpSocketSetup;
-const OutgoingMessage = require('_http_outgoing').OutgoingMessage;
+const {
+  parsers,
+  freeParser,
+  debug,
+  CRLF,
+  continueExpression,
+  chunkExpression,
+  httpSocketSetup,
+  _checkInvalidHeaderChar: checkInvalidHeaderChar
+} = require('_http_common');
+const { OutgoingMessage } = require('_http_outgoing');
 const { outHeadersKey, ondrain } = require('internal/http');
 
 const STATUS_CODES = {
@@ -222,7 +224,7 @@ function writeHead(statusCode, reason, obj) {
     headers = obj;
   }
 
-  if (common._checkInvalidHeaderChar(this.statusMessage))
+  if (checkInvalidHeaderChar(this.statusMessage))
     throw new Error('Invalid character in statusMessage.');
 
   var statusLine = 'HTTP/1.1 ' + statusCode + ' ' + this.statusMessage + CRLF;

lib/_stream_readable.js

@@ -26,7 +26,7 @@ Readable.ReadableState = ReadableState;
 
 const EE = require('events');
 const Stream = require('stream');
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const util = require('util');
 const debug = util.debuglog('stream');
 const BufferList = require('internal/streams/BufferList');

lib/_stream_wrap.js

@@ -2,11 +2,11 @@
 
 const assert = require('assert');
 const util = require('util');
-const Socket = require('net').Socket;
-const JSStream = process.binding('js_stream').JSStream;
 // TODO(bmeurer): Change this back to const once hole checks are
 // properly optimized away early in Ignition+TurboFan.
 var Buffer = require('buffer').Buffer;
+const { Socket } = require('net');
+const { JSStream } = process.binding('js_stream');
 const uv = process.binding('uv');
 const debug = util.debuglog('stream_wrap');
 

lib/_stream_writable.js

@@ -31,7 +31,7 @@ Writable.WritableState = WritableState;
 const util = require('util');
 const internalUtil = require('internal/util');
 const Stream = require('stream');
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const destroyImpl = require('internal/streams/destroy');
 
 util.inherits(Writable, Stream);

lib/_tls_common.js

@@ -23,8 +23,7 @@
 
 const tls = require('tls');
 
-const SSL_OP_CIPHER_SERVER_PREFERENCE =
-    process.binding('constants').crypto.SSL_OP_CIPHER_SERVER_PREFERENCE;
+const { SSL_OP_CIPHER_SERVER_PREFERENCE } = process.binding('constants').crypto;
 
 // Lazily loaded
 var crypto = null;

lib/_tls_legacy.js

@@ -25,12 +25,12 @@ const internalUtil = require('internal/util');
 internalUtil.assertCrypto();
 
 const assert = require('assert');
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const common = require('_tls_common');
-const Connection = process.binding('crypto').Connection;
+const { Connection } = process.binding('crypto');
 const EventEmitter = require('events');
 const stream = require('stream');
-const Timer = process.binding('timer_wrap').Timer;
+const { Timer } = process.binding('timer_wrap');
 const tls = require('tls');
 const util = require('util');
 

lib/_tls_wrap.js

@@ -29,13 +29,13 @@ const net = require('net');
 const tls = require('tls');
 const util = require('util');
 const common = require('_tls_common');
-const StreamWrap = require('_stream_wrap').StreamWrap;
-const Buffer = require('buffer').Buffer;
+const { StreamWrap } = require('_stream_wrap');
+const { Buffer } = require('buffer');
 const debug = util.debuglog('tls');
-const Timer = process.binding('timer_wrap').Timer;
+const { Timer } = process.binding('timer_wrap');
 const tls_wrap = process.binding('tls_wrap');
-const TCP = process.binding('tcp_wrap').TCP;
-const Pipe = process.binding('pipe_wrap').Pipe;
+const { TCP } = process.binding('tcp_wrap');
+const { Pipe } = process.binding('pipe_wrap');
 const kDisableRenegotiation = Symbol('disable-renegotiation');
 
 function onhandshakestart() {

lib/child_process.js

@@ -30,14 +30,17 @@ const debug = util.debuglog('child_process');
 
 const uv = process.binding('uv');
 const spawn_sync = process.binding('spawn_sync');
-const Buffer = require('buffer').Buffer;
-const Pipe = process.binding('pipe_wrap').Pipe;
+const { Buffer } = require('buffer');
+const { Pipe } = process.binding('pipe_wrap');
 const child_process = require('internal/child_process');
+const {
+  _validateStdio,
+  setupChannel,
+  ChildProcess
+} = child_process;
 
 const errnoException = util._errnoException;
-const _validateStdio = child_process._validateStdio;
-const setupChannel = child_process.setupChannel;
-const ChildProcess = exports.ChildProcess = child_process.ChildProcess;
+exports.ChildProcess = ChildProcess;
 
 function stdioStringToArray(option) {
   switch (option) {

lib/dgram.js

@@ -23,18 +23,17 @@
 
 const assert = require('assert');
 const errors = require('internal/errors');
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const dns = require('dns');
 const util = require('util');
 const { isUint8Array } = require('internal/util/types');
 const EventEmitter = require('events');
-const setInitTriggerId = require('async_hooks').setInitTriggerId;
-const UV_UDP_REUSEADDR = process.binding('constants').os.UV_UDP_REUSEADDR;
-const async_id_symbol = process.binding('async_wrap').async_id_symbol;
-const nextTick = require('internal/process/next_tick').nextTick;
+const { setInitTriggerId } = require('async_hooks');
+const { UV_UDP_REUSEADDR } = process.binding('constants').os;
+const { async_id_symbol } = process.binding('async_wrap');
+const { nextTick } = require('internal/process/next_tick');
 
-const UDP = process.binding('udp_wrap').UDP;
-const SendWrap = process.binding('udp_wrap').SendWrap;
+const { UDP, SendWrap } = process.binding('udp_wrap');
 
 const BIND_STATE_UNBOUND = 0;
 const BIND_STATE_BINDING = 1;

lib/dns.js

@@ -25,7 +25,7 @@ const util = require('util');
 
 const cares = process.binding('cares_wrap');
 const uv = process.binding('uv');
-const internalNet = require('internal/net');
+const { isLegalPort } = require('internal/net');
 const { customPromisifyArgs } = require('internal/util');
 
 const {
@@ -36,9 +36,6 @@ const {
   isIP
 } = cares;
 
-const isLegalPort = internalNet.isLegalPort;
-
-
 function errnoException(err, syscall, hostname) {
   // FIXME(bnoordhuis) Remove this backwards compatibility nonsense and pass
   // the true error to the user. ENOTFOUND is not even a proper POSIX error!

lib/domain.js

@@ -28,7 +28,7 @@
 
 const util = require('util');
 const EventEmitter = require('events');
-const inherits = util.inherits;
+const { inherits } = util;
 
 // communicate with events module, but don't require that
 // module to have to load this one, since this module has

lib/fs.js

@@ -33,30 +33,28 @@ const { createPromise, promiseResolve } = process.binding('util');
 
 const binding = process.binding('fs');
 const fs = exports;
-const Buffer = require('buffer').Buffer;
+const { Buffer } = require('buffer');
 const errors = require('internal/errors');
-const Stream = require('stream').Stream;
+const { Readable, Writable } = require('stream');
 const EventEmitter = require('events');
-const FSReqWrap = binding.FSReqWrap;
-const FSEvent = process.binding('fs_event_wrap').FSEvent;
+const { FSReqWrap } = binding;
+const { FSEvent } = process.binding('fs_event_wrap');
 const internalFS = require('internal/fs');
-const internalURL = require('internal/url');
+const { getPathFromURL } = require('internal/url');
 const internalUtil = require('internal/util');
-const assertEncoding = internalFS.assertEncoding;
-const stringToFlags = internalFS.stringToFlags;
-const getPathFromURL = internalURL.getPathFromURL;
+const {
+  assertEncoding,
+  stringToFlags
+} = internalFS;
 
 Object.defineProperty(exports, 'constants', {
   configurable: false,
   enumerable: true,
   value: constants
 });
 
-const Readable = Stream.Readable;
-const Writable = Stream.Writable;
-
 const kMinPoolSpace = 128;
-const kMaxLength = require('buffer').kMaxLength;
+const { kMaxLength } = require('buffer');
 
 const isWindows = process.platform === 'win32';
 

lib/http.js

@@ -22,14 +22,13 @@
 'use strict';
 
 const agent = require('_http_agent');
-const client = require('_http_client');
+const { ClientRequest } = require('_http_client');
 const common = require('_http_common');
 const incoming = require('_http_incoming');
 const outgoing = require('_http_outgoing');
 const server = require('_http_server');
 
-const Server = server.Server;
-const ClientRequest = client.ClientRequest;
+const { Server } = server;
 
 function createServer(requestListener) {
   return new Server(requestListener);

lib/internal/child_process.js

@@ -1,27 +1,25 @@
 'use strict';
 
 const errors = require('internal/errors');
-const StringDecoder = require('string_decoder').StringDecoder;
+const { StringDecoder } = require('string_decoder');
 const EventEmitter = require('events');
 const net = require('net');
 const dgram = require('dgram');
 const util = require('util');
 const assert = require('assert');
-
-const Process = process.binding('process_wrap').Process;
-const WriteWrap = process.binding('stream_wrap').WriteWrap;
 const uv = process.binding('uv');
-const Pipe = process.binding('pipe_wrap').Pipe;
-const TTY = process.binding('tty_wrap').TTY;
-const TCP = process.binding('tcp_wrap').TCP;
-const UDP = process.binding('udp_wrap').UDP;
+const { Process } = process.binding('process_wrap');
+const { WriteWrap } = process.binding('stream_wrap');
+const { Pipe } = process.binding('pipe_wrap');
+const { TTY } = process.binding('tty_wrap');
+const { TCP } = process.binding('tcp_wrap');
+const { UDP } = process.binding('udp_wrap');
 const SocketList = require('internal/socket_list');
 const { convertToValidSignal } = require('internal/util');
 const { isUint8Array } = require('internal/util/types');
 
 const errnoException = util._errnoException;
-const SocketListSend = SocketList.SocketListSend;
-const SocketListReceive = SocketList.SocketListReceive;
+const { SocketListSend, SocketListReceive } = SocketList;
 
 const MAX_HANDLE_RETRANSMISSIONS = 3;
 

lib/internal/cluster/master.js

@@ -1,6 +1,6 @@
 'use strict';
 const assert = require('assert');
-const fork = require('child_process').fork;
+const { fork } = require('child_process');
 const util = require('util');
 const EventEmitter = require('events');
 const RoundRobinHandle = require('internal/cluster/round_robin_handle');