Node.js v18.12.1 Documentation

Table of contents

About this documentation
- Contributing
- Stability index
- Stability overview
- JSON output
- System calls and man pages
Usage and example
- Usage
- Example
Assert
- Strict assertion mode
- Legacy assertion mode
- Class: assert.AssertionError
  - new assert.AssertionError(options)
- Class: assert.CallTracker
  - new assert.CallTracker()
  - tracker.calls([fn][, exact])
  - tracker.getCalls(fn)
  - tracker.report()
  - tracker.reset([fn])
  - tracker.verify()
- assert(value[, message])
- assert.deepEqual(actual, expected[, message])
  - Comparison details
- assert.deepStrictEqual(actual, expected[, message])
  - Comparison details
- assert.doesNotMatch(string, regexp[, message])
- assert.doesNotReject(asyncFn[, error][, message])
- assert.doesNotThrow(fn[, error][, message])
- assert.equal(actual, expected[, message])
- assert.fail([message])
- assert.fail(actual, expected[, message[, operator[, stackStartFn]]])
- assert.ifError(value)
- assert.match(string, regexp[, message])
- assert.notDeepEqual(actual, expected[, message])
- assert.notDeepStrictEqual(actual, expected[, message])
- assert.notEqual(actual, expected[, message])
- assert.notStrictEqual(actual, expected[, message])
- assert.ok(value[, message])
- assert.rejects(asyncFn[, error][, message])
- assert.snapshot(value, name)
- assert.strictEqual(actual, expected[, message])
- assert.throws(fn[, error][, message])
Asynchronous context tracking
- Introduction
- Class: AsyncLocalStorage
- Class: AsyncResource
Async hooks
- Terminology
- Overview
- async_hooks.createHook(callbacks)
  - Error handling
  - Printing in AsyncHook callbacks
- Class: AsyncHook
- Promise execution tracking
- JavaScript embedder API
  - Class: AsyncResource
- Class: AsyncLocalStorage
Buffer
- Buffers and character encodings
- Buffers and TypedArrays
- Buffers and iteration
- Class: Blob
- Class: Buffer
- node:buffer module APIs
- Buffer.from(), Buffer.alloc(), and Buffer.allocUnsafe()
  - The --zero-fill-buffers command-line option
  - What makes Buffer.allocUnsafe() and Buffer.allocUnsafeSlow() "unsafe"?
C++ addons
- Hello world
- Native abstractions for Node.js
- Node-API
- Addon examples
Node-API
- Implications of ABI stability
- Building
  - Build tools
    - node-gyp
    - CMake.js
  - Uploading precompiled binaries
- Usage
- Node-API version matrix
- Environment life cycle APIs
  - napi_set_instance_data
  - napi_get_instance_data
- Basic Node-API data types
  - napi_status
  - napi_extended_error_info
  - napi_env
  - napi_value
  - napi_threadsafe_function
  - napi_threadsafe_function_release_mode
  - napi_threadsafe_function_call_mode
  - Node-API memory management types
  - Node-API callback types
- Error handling
  - Return values
    - napi_get_last_error_info
  - Exceptions
  - Fatal errors
    - napi_fatal_error
- Object lifetime management
  - Making handle lifespan shorter than that of the native method
  - References to objects with a lifespan longer than that of the native method
  - Cleanup on exit of the current Node.js instance
- Module registration
- Working with JavaScript values
  - Enum types
  - Object creation functions
  - Functions to convert from C types to Node-API
  - Functions to convert from Node-API to C types
  - Functions to get global instances
- Working with JavaScript values and abstract operations
  - napi_coerce_to_bool
  - napi_coerce_to_number
  - napi_coerce_to_object
  - napi_coerce_to_string
  - napi_typeof
  - napi_instanceof
  - napi_is_array
  - napi_is_arraybuffer
  - napi_is_buffer
  - napi_is_date
  - napi_is_error
  - napi_is_typedarray
  - napi_is_dataview
  - napi_strict_equals
  - napi_detach_arraybuffer
  - napi_is_detached_arraybuffer
- Working with JavaScript properties
  - Structures
    - napi_property_attributes
    - napi_property_descriptor
  - Functions
- Working with JavaScript functions
  - napi_call_function
  - napi_create_function
  - napi_get_cb_info
  - napi_get_new_target
  - napi_new_instance
- Object wrap
  - napi_define_class
  - napi_wrap
  - napi_unwrap
  - napi_remove_wrap
  - napi_type_tag_object
  - napi_check_object_type_tag
  - napi_add_finalizer
- Simple asynchronous operations
  - napi_create_async_work
  - napi_delete_async_work
  - napi_queue_async_work
  - napi_cancel_async_work
- Custom asynchronous operations
  - napi_async_init
  - napi_async_destroy
  - napi_make_callback
  - napi_open_callback_scope
  - napi_close_callback_scope
- Version management
  - napi_get_node_version
  - napi_get_version
- Memory management
  - napi_adjust_external_memory
- Promises
  - napi_create_promise
  - napi_resolve_deferred
  - napi_reject_deferred
  - napi_is_promise
- Script execution
  - napi_run_script
- libuv event loop
  - napi_get_uv_event_loop
- Asynchronous thread-safe function calls
  - Calling a thread-safe function
  - Reference counting of thread-safe functions
  - Deciding whether to keep the process running
  - napi_create_threadsafe_function
  - napi_get_threadsafe_function_context
  - napi_call_threadsafe_function
  - napi_acquire_threadsafe_function
  - napi_release_threadsafe_function
  - napi_ref_threadsafe_function
  - napi_unref_threadsafe_function
- Miscellaneous utilities
  - node_api_get_module_file_name
C++ embedder API
- Example embedding application
  - Setting up per-process state
  - Per-instance state
Child process
- Asynchronous process creation
- Synchronous process creation
- Class: ChildProcess
- maxBuffer and Unicode
- Shell requirements
- Default Windows shell
- Advanced serialization
Cluster
- How it works
- Class: Worker
  - Event: 'disconnect'
  - Event: 'error'
  - Event: 'exit'
  - Event: 'listening'
  - Event: 'message'
  - Event: 'online'
  - worker.disconnect()
  - worker.exitedAfterDisconnect
  - worker.id
  - worker.isConnected()
  - worker.isDead()
  - worker.kill([signal])
  - worker.process
  - worker.send(message[, sendHandle[, options]][, callback])
- Event: 'disconnect'
- Event: 'exit'
- Event: 'fork'
- Event: 'listening'
- Event: 'message'
- Event: 'online'
- Event: 'setup'
- cluster.disconnect([callback])
- cluster.fork([env])
- cluster.isMaster
- cluster.isPrimary
- cluster.isWorker
- cluster.schedulingPolicy
- cluster.settings
- cluster.setupMaster([settings])
- cluster.setupPrimary([settings])
- cluster.worker
- cluster.workers
Command-line API
- Synopsis
- Program entry point
  - ECMAScript modules loader entry point caveat
- Options
- Environment variables
- Useful V8 options
  - --max-old-space-size=SIZE (in megabytes)
  - --max-semi-space-size=SIZE (in megabytes)
Console
- Class: Console
- Inspector only methods
Corepack
- Workflows
- Supported package managers
- Common questions
  - How does Corepack interact with npm?
  - Running npm install -g yarn doesn't work
Crypto
- Determining if crypto support is unavailable
- Class: Certificate
- Class: Cipher
- Class: Decipher
- Class: DiffieHellman
- Class: DiffieHellmanGroup
- Class: ECDH
- Class: Hash
- Class: Hmac
  - hmac.digest([encoding])
  - hmac.update(data[, inputEncoding])
- Class: KeyObject
- Class: Sign
  - sign.sign(privateKey[, outputEncoding])
  - sign.update(data[, inputEncoding])
- Class: Verify
  - verify.update(data[, inputEncoding])
  - verify.verify(object, signature[, signatureEncoding])
- Class: X509Certificate
- node:crypto module methods and properties
- Notes
- Crypto constants
Debugger
- Watchers
- Command reference
- Advanced usage
  - V8 inspector integration for Node.js
Deprecated APIs
- Revoking deprecations
- List of deprecated APIs
Diagnostics Channel
- Public API
DNS
- Class: dns.Resolver
  - Resolver([options])
  - resolver.cancel()
  - resolver.setLocalAddress([ipv4][, ipv6])
- dns.getServers()
- dns.lookup(hostname[, options], callback)
  - Supported getaddrinfo flags
- dns.lookupService(address, port, callback)
- dns.resolve(hostname[, rrtype], callback)
- dns.resolve4(hostname[, options], callback)
- dns.resolve6(hostname[, options], callback)
- dns.resolveAny(hostname, callback)
- dns.resolveCname(hostname, callback)
- dns.resolveCaa(hostname, callback)
- dns.resolveMx(hostname, callback)
- dns.resolveNaptr(hostname, callback)
- dns.resolveNs(hostname, callback)
- dns.resolvePtr(hostname, callback)
- dns.resolveSoa(hostname, callback)
- dns.resolveSrv(hostname, callback)
- dns.resolveTxt(hostname, callback)
- dns.reverse(ip, callback)
- dns.setDefaultResultOrder(order)
- dns.setServers(servers)
- DNS promises API
  - Class: dnsPromises.Resolver
  - resolver.cancel()
  - dnsPromises.getServers()
  - dnsPromises.lookup(hostname[, options])
  - dnsPromises.lookupService(address, port)
  - dnsPromises.resolve(hostname[, rrtype])
  - dnsPromises.resolve4(hostname[, options])
  - dnsPromises.resolve6(hostname[, options])
  - dnsPromises.resolveAny(hostname)
  - dnsPromises.resolveCaa(hostname)
  - dnsPromises.resolveCname(hostname)
  - dnsPromises.resolveMx(hostname)
  - dnsPromises.resolveNaptr(hostname)
  - dnsPromises.resolveNs(hostname)
  - dnsPromises.resolvePtr(hostname)
  - dnsPromises.resolveSoa(hostname)
  - dnsPromises.resolveSrv(hostname)
  - dnsPromises.resolveTxt(hostname)
  - dnsPromises.reverse(ip)
  - dnsPromises.setDefaultResultOrder(order)
  - dnsPromises.setServers(servers)
- Error codes
- Implementation considerations
  - dns.lookup()
  - dns.resolve(), dns.resolve*(), and dns.reverse()
Domain
- Warning: Don't ignore errors!
- Additions to Error objects
- Implicit binding
- Explicit binding
- domain.create()
- Class: Domain
- Domains and promises
Errors
- Error propagation and interception
  - Error-first callbacks
- Class: Error
- Class: AssertionError
- Class: RangeError
- Class: ReferenceError
- Class: SyntaxError
- Class: SystemError
- Class: TypeError
- Exceptions vs. errors
- OpenSSL errors
- Node.js error codes
- Legacy Node.js error codes
Events
- Passing arguments and this to listeners
- Asynchronous vs. synchronous
- Handling events only once
- Error events
- Capture rejections of promises
- Class: EventEmitter
- events.defaultMaxListeners
- events.errorMonitor
- events.getEventListeners(emitterOrTarget, eventName)
- events.once(emitter, name[, options])
  - Awaiting multiple events emitted on process.nextTick()
- events.captureRejections
- events.captureRejectionSymbol
- events.listenerCount(emitter, eventName)
- events.on(emitter, eventName[, options])
- events.setMaxListeners(n[, ...eventTargets])
- Class: events.EventEmitterAsyncResource extends EventEmitter
- EventTarget and Event API
File system
- Promise example
- Callback example
- Synchronous example
- Promises API
- Callback API
- Synchronous API
- Common Objects
- Notes
Global objects
- Class: AbortController
  - abortController.abort([reason])
  - abortController.signal
  - Class: AbortSignal
- Class: Blob
- Class: Buffer
- Class: ByteLengthQueuingStrategy
- __dirname
- __filename
- atob(data)
- BroadcastChannel
- btoa(data)
- clearImmediate(immediateObject)
- clearInterval(intervalObject)
- clearTimeout(timeoutObject)
- Class: CompressionStream
- console
- Class: CountQueuingStrategy
- Crypto
- crypto
- CryptoKey
- CustomEvent
- Class: DecompressionStream
- Event
- EventTarget
- exports
- fetch
- Class FormData
- global
- Class Headers
- MessageChannel
- MessageEvent
- MessagePort
- module
- performance
- process
- queueMicrotask(callback)
- Class: ReadableByteStreamController
- Class: ReadableStream
- Class: ReadableStreamBYOBReader
- Class: ReadableStreamBYOBRequest
- Class: ReadableStreamDefaultController
- Class: ReadableStreamDefaultReader
- require()
- Response
- Request
- setImmediate(callback[, ...args])
- setInterval(callback, delay[, ...args])
- setTimeout(callback, delay[, ...args])
- structuredClone(value[, options])
- SubtleCrypto
- DOMException
- TextDecoder
- Class: TextDecoderStream
- TextEncoder
- Class: TextEncoderStream
- Class: TransformStream
- Class: TransformStreamDefaultController
- URL
- URLSearchParams
- WebAssembly
- Class: WritableStream
- Class: WritableStreamDefaultController
- Class: WritableStreamDefaultWriter
HTTP
- Class: http.Agent
- Class: http.ClientRequest
- Class: http.Server
- Class: http.ServerResponse
- Class: http.IncomingMessage
- Class: http.OutgoingMessage
- http.METHODS
- http.STATUS_CODES
- http.createServer([options][, requestListener])
- http.get(options[, callback])
- http.get(url[, options][, callback])
- http.globalAgent
- http.maxHeaderSize
- http.request(options[, callback])
- http.request(url[, options][, callback])
- http.validateHeaderName(name)
- http.validateHeaderValue(name, value)
- http.setMaxIdleHTTPParsers
HTTP/2
- Determining if crypto support is unavailable
- Core API
- Compatibility API
- Collecting HTTP/2 performance metrics
- Note on :authority and host
HTTPS
- Determining if crypto support is unavailable
- Class: https.Agent
  - new Agent([options])
    - Event: 'keylog'
- Class: https.Server
- https.createServer([options][, requestListener])
- https.get(options[, callback])
- https.get(url[, options][, callback])
- https.globalAgent
- https.request(options[, callback])
- https.request(url[, options][, callback])
Inspector
- inspector.close()
- inspector.console
- inspector.open([port[, host[, wait]]])
- inspector.url()
- inspector.waitForDebugger()
- Class: inspector.Session
- Example usage
  - CPU profiler
  - Heap profiler
Internationalization support
- Options for building Node.js
- Detecting internationalization support
Modules: CommonJS modules
- Enabling
- Accessing the main module
- Package manager tips
- The .mjs extension
- All together
- Caching
  - Module caching caveats
- Core modules
- Cycles
- File modules
- Folders as modules
- Loading from node_modules folders
- Loading from the global folders
- The module wrapper
- The module scope
- The module object
- The Module object
- Source map v3 support
Modules: ECMAScript modules
- Introduction
- Enabling
- Packages
- import Specifiers
- Import assertions
- Builtin modules
- import() expressions
- import.meta
  - import.meta.url
  - import.meta.resolve(specifier[, parent])
- Interoperability with CommonJS
- JSON modules
- Wasm modules
- Top-level await
- HTTPS and HTTP imports
- Loaders
  - Hooks
  - Examples
    - HTTPS loader
    - Transpiler loader
- Resolution algorithm
Modules: node:module API
- The Module object
- Source map v3 support
  - module.findSourceMap(path)
  - Class: module.SourceMap
Modules: Packages
- Introduction
- Determining module system
- Determining package manager
- Package entry points
- Dual CommonJS/ES module packages
  - Dual package hazard
  - Writing dual packages while avoiding or minimizing hazards
    - Approach #1: Use an ES module wrapper
    - Approach #2: Isolate state
- Node.js package.json field definitions
Net
- IPC support
  - Identifying paths for IPC connections
- Class: net.BlockList
- Class: net.SocketAddress
- Class: net.Server
- Class: net.Socket
- net.connect()
- net.createConnection()
- net.createServer([options][, connectionListener])
- net.isIP(input)
- net.isIPv4(input)
- net.isIPv6(input)
OS
- os.EOL
- os.arch()
- os.constants
- os.cpus()
- os.devNull
- os.endianness()
- os.freemem()
- os.getPriority([pid])
- os.homedir()
- os.hostname()
- os.loadavg()
- os.networkInterfaces()
- os.platform()
- os.release()
- os.setPriority([pid, ]priority)
- os.tmpdir()
- os.totalmem()
- os.type()
- os.uptime()
- os.userInfo([options])
- os.version()
- os.machine()
- OS constants
  - Signal constants
  - Error constants
    - POSIX error constants
    - Windows-specific error constants
  - dlopen constants
  - Priority constants
  - libuv constants
Path
- Windows vs. POSIX
- path.basename(path[, suffix])
- path.delimiter
- path.dirname(path)
- path.extname(path)
- path.format(pathObject)
- path.isAbsolute(path)
- path.join([...paths])
- path.normalize(path)
- path.parse(path)
- path.posix
- path.relative(from, to)
- path.resolve([...paths])
- path.sep
- path.toNamespacedPath(path)
- path.win32
Performance measurement APIs
- perf_hooks.performance
- Class: PerformanceEntry
- Class: PerformanceNodeTiming
- Class: PerformanceResourceTiming
- Class: perf_hooks.PerformanceObserver
- Class: PerformanceObserverEntryList
- perf_hooks.createHistogram([options])
- perf_hooks.monitorEventLoopDelay([options])
- Class: Histogram
- Class: IntervalHistogram extends Histogram
- Class: RecordableHistogram extends Histogram
- Examples
Permissions
- Module-based permissions
  - Policies
Process
- Process events
  - Event: 'beforeExit'
  - Event: 'disconnect'
  - Event: 'exit'
  - Event: 'message'
  - Event: 'multipleResolves'
  - Event: 'rejectionHandled'
  - Event: 'uncaughtException'
    - Warning: Using 'uncaughtException' correctly
  - Event: 'uncaughtExceptionMonitor'
  - Event: 'unhandledRejection'
  - Event: 'warning'
  - Event: 'worker'
    - Emitting custom warnings
    - Node.js warning names
  - Signal events
- process.abort()
- process.allowedNodeEnvironmentFlags
- process.arch
- process.argv
- process.argv0
- process.channel
  - process.channel.ref()
  - process.channel.unref()
- process.chdir(directory)
- process.config
- process.connected
- process.cpuUsage([previousValue])
- process.cwd()
- process.debugPort
- process.disconnect()
- process.dlopen(module, filename[, flags])
- process.emitWarning(warning[, options])
- process.emitWarning(warning[, type[, code]][, ctor])
  - Avoiding duplicate warnings
- process.env
- process.execArgv
- process.execPath
- process.exit([code])
- process.exitCode
- process.getActiveResourcesInfo()
- process.getegid()
- process.geteuid()
- process.getgid()
- process.getgroups()
- process.getuid()
- process.hasUncaughtExceptionCaptureCallback()
- process.hrtime([time])
- process.hrtime.bigint()
- process.initgroups(user, extraGroup)
- process.kill(pid[, signal])
- process.mainModule
- process.memoryUsage()
- process.memoryUsage.rss()
- process.nextTick(callback[, ...args])
  - When to use queueMicrotask() vs. process.nextTick()
- process.noDeprecation
- process.pid
- process.platform
- process.ppid
- process.release
- process.report
  - process.report.compact
  - process.report.directory
  - process.report.filename
  - process.report.getReport([err])
  - process.report.reportOnFatalError
  - process.report.reportOnSignal
  - process.report.reportOnUncaughtException
  - process.report.signal
  - process.report.writeReport([filename][, err])
- process.resourceUsage()
- process.send(message[, sendHandle[, options]][, callback])
- process.setegid(id)
- process.seteuid(id)
- process.setgid(id)
- process.setgroups(groups)
- process.setuid(id)
- process.setSourceMapsEnabled(val)
- process.setUncaughtExceptionCaptureCallback(fn)
- process.stderr
  - process.stderr.fd
- process.stdin
  - process.stdin.fd
- process.stdout
  - process.stdout.fd
  - A note on process I/O
- process.throwDeprecation
- process.title
- process.traceDeprecation
- process.umask()
- process.umask(mask)
- process.uptime()
- process.version
- process.versions
- Exit codes
Punycode
- punycode.decode(string)
- punycode.encode(string)
- punycode.toASCII(domain)
- punycode.toUnicode(domain)
- punycode.ucs2
  - punycode.ucs2.decode(string)
  - punycode.ucs2.encode(codePoints)
- punycode.version
Query string
- querystring.decode()
- querystring.encode()
- querystring.escape(str)
- querystring.parse(str[, sep[, eq[, options]]])
- querystring.stringify(obj[, sep[, eq[, options]]])
- querystring.unescape(str)
Readline
- Class: InterfaceConstructor
- Promises API
- Callback API
- readline.emitKeypressEvents(stream[, interface])
- Example: Tiny CLI
- Example: Read file stream line-by-Line
- TTY keybindings
REPL
- Design and features
- Class: REPLServer
- repl.builtinModules
- repl.start([options])
- The Node.js REPL
Diagnostic report
- Usage
- Configuration
- Interaction with workers
Stream
- Organization of this document
- Types of streams
- API for stream consumers
- API for stream implementers
- Additional notes
String decoder
- Class: StringDecoder
Test runner
- Subtests
- Skipping tests
- describe/it syntax
  - only tests
- Filtering tests by name
- Extraneous asynchronous activity
- Running tests from the command line
  - Test runner execution model
- run([options])
- test([name][, options][, fn])
- describe([name][, options][, fn])
- describe.skip([name][, options][, fn])
- describe.todo([name][, options][, fn])
- it([name][, options][, fn])
- it.skip([name][, options][, fn])
- it.todo([name][, options][, fn])
- before([fn][, options])
- after([fn][, options])
- beforeEach([fn][, options])
- afterEach([fn][, options])
- Class: TapStream
  - Event: 'test:diagnostic'
  - Event: 'test:fail'
  - Event: 'test:pass'
- Class: TestContext
  - context.beforeEach([fn][, options])
  - context.afterEach([fn][, options])
  - context.diagnostic(message)
  - context.name
  - context.runOnly(shouldRunOnlyTests)
  - context.signal
  - context.skip([message])
  - context.todo([message])
  - context.test([name][, options][, fn])
- Class: SuiteContext
  - context.name
  - context.signal
Timers
- Class: Immediate
- Class: Timeout
- Scheduling timers
- Cancelling timers
- Timers Promises API
TLS (SSL)
- Determining if crypto support is unavailable
- TLS/SSL concepts
  - Perfect forward secrecy
  - ALPN and SNI
  - Pre-shared keys
  - Client-initiated renegotiation attack mitigation
  - Session resumption
    - Session identifiers
    - Session tickets
- Modifying the default TLS cipher suite
- X509 certificate error codes
- Class: tls.CryptoStream
  - cryptoStream.bytesWritten
- Class: tls.SecurePair
  - Event: 'secure'
- Class: tls.Server
  - Event: 'connection'
  - Event: 'keylog'
  - Event: 'newSession'
  - Event: 'OCSPRequest'
  - Event: 'resumeSession'
  - Event: 'secureConnection'
  - Event: 'tlsClientError'
  - server.addContext(hostname, context)
  - server.address()
  - server.close([callback])
  - server.getTicketKeys()
  - server.listen()
  - server.setSecureContext(options)
  - server.setTicketKeys(keys)
- Class: tls.TLSSocket
  - new tls.TLSSocket(socket[, options])
  - Event: 'keylog'
  - Event: 'OCSPResponse'
  - Event: 'secureConnect'
  - Event: 'session'
  - tlsSocket.address()
  - tlsSocket.authorizationError
  - tlsSocket.authorized
  - tlsSocket.disableRenegotiation()
  - tlsSocket.enableTrace()
  - tlsSocket.encrypted
  - tlsSocket.exportKeyingMaterial(length, label[, context])
  - tlsSocket.getCertificate()
  - tlsSocket.getCipher()
  - tlsSocket.getEphemeralKeyInfo()
  - tlsSocket.getFinished()
  - tlsSocket.getPeerCertificate([detailed])
    - Certificate object
  - tlsSocket.getPeerFinished()
  - tlsSocket.getPeerX509Certificate()
  - tlsSocket.getProtocol()
  - tlsSocket.getSession()
  - tlsSocket.getSharedSigalgs()
  - tlsSocket.getTLSTicket()
  - tlsSocket.getX509Certificate()
  - tlsSocket.isSessionReused()
  - tlsSocket.localAddress
  - tlsSocket.localPort
  - tlsSocket.remoteAddress
  - tlsSocket.remoteFamily
  - tlsSocket.remotePort
  - tlsSocket.renegotiate(options, callback)
  - tlsSocket.setMaxSendFragment(size)
- tls.checkServerIdentity(hostname, cert)
- tls.connect(options[, callback])
- tls.connect(path[, options][, callback])
- tls.connect(port[, host][, options][, callback])
- tls.createSecureContext([options])
- tls.createSecurePair([context][, isServer][, requestCert][, rejectUnauthorized][, options])
- tls.createServer([options][, secureConnectionListener])
- tls.getCiphers()
- tls.rootCertificates
- tls.DEFAULT_ECDH_CURVE
- tls.DEFAULT_MAX_VERSION
- tls.DEFAULT_MIN_VERSION
Trace events
- The node:trace_events module
- Examples
  - Collect trace events data by inspector
TTY
- Class: tty.ReadStream
- Class: tty.WriteStream
- tty.isatty(fd)
UDP/datagram sockets
- Class: dgram.Socket
- node:dgram module functions
  - dgram.createSocket(options[, callback])
  - dgram.createSocket(type[, callback])
URL
- URL strings and URL objects
  - Constructing a URL from component parts and getting the constructed string
- The WHATWG URL API
- Legacy URL API
- Percent-encoding in URLs
  - Legacy API
  - WHATWG API
Util
- util.callbackify(original)
- util.debuglog(section[, callback])
  - debuglog().enabled
- util.debug(section)
- util.deprecate(fn, msg[, code])
- util.format(format[, ...args])
- util.formatWithOptions(inspectOptions, format[, ...args])
- util.getSystemErrorName(err)
- util.getSystemErrorMap()
- util.inherits(constructor, superConstructor)
- util.inspect(object[, options])
- util.inspect(object[, showHidden[, depth[, colors]]])
  - Customizing util.inspect colors
  - Custom inspection functions on objects
  - util.inspect.custom
  - util.inspect.defaultOptions
- util.isDeepStrictEqual(val1, val2)
- util.parseArgs([config])
  - parseArgs tokens
- util.promisify(original)
  - Custom promisified functions
  - util.promisify.custom
- util.stripVTControlCharacters(str)
- Class: util.TextDecoder
  - WHATWG supported encodings
  - new TextDecoder([encoding[, options]])
  - textDecoder.decode([input[, options]])
  - textDecoder.encoding
  - textDecoder.fatal
  - textDecoder.ignoreBOM
- Class: util.TextEncoder
  - textEncoder.encode([input])
  - textEncoder.encodeInto(src, dest)
  - textEncoder.encoding
- util.toUSVString(string)
- util.transferableAbortController()
- util.transferableAbortSignal(signal)
- util.types
  - util.types.isAnyArrayBuffer(value)
  - util.types.isArrayBufferView(value)
  - util.types.isArgumentsObject(value)
  - util.types.isArrayBuffer(value)
  - util.types.isAsyncFunction(value)
  - util.types.isBigInt64Array(value)
  - util.types.isBigUint64Array(value)
  - util.types.isBooleanObject(value)
  - util.types.isBoxedPrimitive(value)
  - util.types.isCryptoKey(value)
  - util.types.isDataView(value)
  - util.types.isDate(value)
  - util.types.isExternal(value)
  - util.types.isFloat32Array(value)
  - util.types.isFloat64Array(value)
  - util.types.isGeneratorFunction(value)
  - util.types.isGeneratorObject(value)
  - util.types.isInt8Array(value)
  - util.types.isInt16Array(value)
  - util.types.isInt32Array(value)
  - util.types.isKeyObject(value)
  - util.types.isMap(value)
  - util.types.isMapIterator(value)
  - util.types.isModuleNamespaceObject(value)
  - util.types.isNativeError(value)
  - util.types.isNumberObject(value)
  - util.types.isPromise(value)
  - util.types.isProxy(value)
  - util.types.isRegExp(value)
  - util.types.isSet(value)
  - util.types.isSetIterator(value)
  - util.types.isSharedArrayBuffer(value)
  - util.types.isStringObject(value)
  - util.types.isSymbolObject(value)
  - util.types.isTypedArray(value)
  - util.types.isUint8Array(value)
  - util.types.isUint8ClampedArray(value)
  - util.types.isUint16Array(value)
  - util.types.isUint32Array(value)
  - util.types.isWeakMap(value)
  - util.types.isWeakSet(value)
  - util.types.isWebAssemblyCompiledModule(value)
- Deprecated APIs
  - util._extend(target, source)
  - util.isArray(object)
  - util.isBoolean(object)
  - util.isBuffer(object)
  - util.isDate(object)
  - util.isError(object)
  - util.isFunction(object)
  - util.isNull(object)
  - util.isNullOrUndefined(object)
  - util.isNumber(object)
  - util.isObject(object)
  - util.isPrimitive(object)
  - util.isRegExp(object)
  - util.isString(object)
  - util.isSymbol(object)
  - util.isUndefined(object)
  - util.log(string)
V8
- v8.cachedDataVersionTag()
- v8.getHeapCodeStatistics()
- v8.getHeapSnapshot()
- v8.getHeapSpaceStatistics()
- v8.getHeapStatistics()
- v8.setFlagsFromString(flags)
- v8.stopCoverage()
- v8.takeCoverage()
- v8.writeHeapSnapshot([filename])
- v8.setHeapSnapshotNearHeapLimit(limit)
- Serialization API
- Promise hooks
- Startup Snapshot API
VM (executing JavaScript)
- Class: vm.Script
- Class: vm.Module
- Class: vm.SourceTextModule
  - new vm.SourceTextModule(code[, options])
  - sourceTextModule.createCachedData()
- Class: vm.SyntheticModule
  - new vm.SyntheticModule(exportNames, evaluateCallback[, options])
  - syntheticModule.setExport(name, value)
- vm.compileFunction(code[, params[, options]])
- vm.createContext([contextObject[, options]])
- vm.isContext(object)
- vm.measureMemory([options])
- vm.runInContext(code, contextifiedObject[, options])
- vm.runInNewContext(code[, contextObject[, options]])
- vm.runInThisContext(code[, options])
- Example: Running an HTTP server within a VM
- What does it mean to "contextify" an object?
- Timeout interactions with asynchronous tasks and Promises
WebAssembly System Interface (WASI)
- Class: WASI
Web Crypto API
- Examples
- Algorithm matrix
- Class: Crypto
- Class: CryptoKey
- Class: CryptoKeyPair
  - cryptoKeyPair.privateKey
  - cryptoKeyPair.publicKey
- Class: SubtleCrypto
- Algorithm parameters
Web Streams API
- Overview
  - Example ReadableStream
- API
Worker threads
- worker.getEnvironmentData(key)
- worker.isMainThread
- worker.markAsUntransferable(object)
- worker.moveMessagePortToContext(port, contextifiedSandbox)
- worker.parentPort
- worker.receiveMessageOnPort(port)
- worker.resourceLimits
- worker.SHARE_ENV
- worker.setEnvironmentData(key[, value])
- worker.threadId
- worker.workerData
- Class: BroadcastChannel extends EventTarget
- Class: MessageChannel
- Class: MessagePort
- Class: Worker
- Notes
  - Synchronous blocking of stdio
  - Launching worker threads from preload scripts
Zlib
- Threadpool usage and performance considerations
- Compressing HTTP requests and responses
- Memory usage tuning
  - For zlib-based streams
  - For Brotli-based streams
- Flushing
- Constants
  - zlib constants
  - Brotli constants
- Class: Options
- Class: BrotliOptions
- Class: zlib.BrotliCompress
- Class: zlib.BrotliDecompress
- Class: zlib.Deflate
- Class: zlib.DeflateRaw
- Class: zlib.Gunzip
- Class: zlib.Gzip
- Class: zlib.Inflate
- Class: zlib.InflateRaw
- Class: zlib.Unzip
- Class: zlib.ZlibBase
  - zlib.bytesRead
  - zlib.bytesWritten
  - zlib.close([callback])
  - zlib.flush([kind, ]callback)
  - zlib.params(level, strategy, callback)
  - zlib.reset()
- zlib.constants
- zlib.createBrotliCompress([options])
- zlib.createBrotliDecompress([options])
- zlib.createDeflate([options])
- zlib.createDeflateRaw([options])
- zlib.createGunzip([options])
- zlib.createGzip([options])
- zlib.createInflate([options])
- zlib.createInflateRaw([options])
- zlib.createUnzip([options])
- Convenience methods
  - zlib.brotliCompress(buffer[, options], callback)
  - zlib.brotliCompressSync(buffer[, options])
  - zlib.brotliDecompress(buffer[, options], callback)
  - zlib.brotliDecompressSync(buffer[, options])
  - zlib.deflate(buffer[, options], callback)
  - zlib.deflateSync(buffer[, options])
  - zlib.deflateRaw(buffer[, options], callback)
  - zlib.deflateRawSync(buffer[, options])
  - zlib.gunzip(buffer[, options], callback)
  - zlib.gunzipSync(buffer[, options])
  - zlib.gzip(buffer[, options], callback)
  - zlib.gzipSync(buffer[, options])
  - zlib.inflate(buffer[, options], callback)
  - zlib.inflateSync(buffer[, options])
  - zlib.inflateRaw(buffer[, options], callback)
  - zlib.inflateRawSync(buffer[, options])
  - zlib.unzip(buffer[, options], callback)
  - zlib.unzipSync(buffer[, options])