Node.js v19.0.1 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