Node.js v10.1.0 Documentation

Table of Contents

Deprecated APIs#

Node.js may deprecate APIs when either: (a) use of the API is considered to be unsafe, (b) an improved alternative API has been made available, or (c) breaking changes to the API are expected in a future major release.

Node.js utilizes three kinds of Deprecations:

  • Documentation-only
  • Runtime
  • End-of-Life

A Documentation-only deprecation is one that is expressed only within the Node.js API docs. These generate no side-effects while running Node.js. Some Documentation-only deprecations trigger a runtime warning when launched with --pending-deprecation flag (or its alternative, NODE_PENDING_DEPRECATION=1 environment variable), similarly to Runtime deprecations below. Documentation-only deprecations that support that flag are explicitly labeled as such in the list of Deprecated APIs.

A Runtime deprecation will, by default, generate a process warning that will be printed to stderr the first time the deprecated API is used. When the --throw-deprecation command-line flag is used, a Runtime deprecation will cause an error to be thrown.

An End-of-Life deprecation is used to identify code that either has been removed or will soon be removed from Node.js.

Revoking deprecations#

Occasionally, the deprecation of an API may be reversed. In such situations, this document will be updated with information relevant to the decision. However, the deprecation identifier will not be modified.

List of Deprecated APIs#

DEP0001: http.OutgoingMessage.prototype.flush#

Type: Runtime

The OutgoingMessage.prototype.flush() method is deprecated. Use OutgoingMessage.prototype.flushHeaders() instead.

DEP0002: require('_linklist')#

Type: End-of-Life

The _linklist module is deprecated. Please use a userland alternative.

DEP0003: _writableState.buffer#

Type: Runtime

The _writableState.buffer property is deprecated. Use the _writableState.getBuffer() method instead.

DEP0004: CryptoStream.prototype.readyState#

Type: Documentation-only

The CryptoStream.prototype.readyState property is deprecated and should not be used.

DEP0005: Buffer() constructor#

Type: Runtime (supports --pending-deprecation)

The Buffer() function and new Buffer() constructor are deprecated due to API usability issues that can potentially lead to accidental security issues.

As an alternative, use of the following methods of constructing Buffer objects is strongly recommended:

As of v10.0.0, a deprecation warning is printed at runtime when --pending-deprecation is used or when the calling code is outside node_modules in order to better target developers, rather than users.

DEP0006: child_process options.customFds#

Type: Runtime

Within the child_process module's spawn(), fork(), and exec() methods, the options.customFds option is deprecated. The options.stdio option should be used instead.

DEP0007: Replace cluster worker.suicide with worker.exitedAfterDisconnect#

Type: End-of-Life

In an earlier version of the Node.js cluster, a boolean property with the name suicide was added to the Worker object. The intent of this property was to provide an indication of how and why the Worker instance exited. In Node.js 6.0.0, the old property was deprecated and replaced with a new worker.exitedAfterDisconnect property. The old property name did not precisely describe the actual semantics and was unnecessarily emotion-laden.

DEP0008: require('constants')#

Type: Documentation-only

The constants module has been deprecated. When requiring access to constants relevant to specific Node.js builtin modules, developers should instead refer to the constants property exposed by the relevant module. For instance, require('fs').constants and require('os').constants.

DEP0009: crypto.pbkdf2 without digest#

Type: End-of-Life

Use of the crypto.pbkdf2() API without specifying a digest was deprecated in Node.js 6.0 because the method defaulted to using the non-recommended 'SHA1' digest. Previously, a deprecation warning was printed. Starting in Node.js 8.0.0, calling crypto.pbkdf2() or crypto.pbkdf2Sync() with an undefined digest will throw a TypeError.

DEP0010: crypto.createCredentials#

Type: Runtime

The crypto.createCredentials() API is deprecated. Please use tls.createSecureContext() instead.

DEP0011: crypto.Credentials#

Type: Runtime

The crypto.Credentials class is deprecated. Please use tls.SecureContext instead.

DEP0012: Domain.dispose#

Type: End-of-Life

Domain.dispose() has been removed. Recover from failed I/O actions explicitly via error event handlers set on the domain instead.

DEP0013: fs asynchronous function without callback#

Type: End-of-Life

Calling an asynchronous function without a callback throws a TypeError in Node.js 10.0.0 onwards. (See https://github.com/nodejs/node/pull/12562.)

DEP0014: fs.read legacy String interface#

Type: End-of-Life

The fs.read() legacy String interface is deprecated. Use the Buffer API as mentioned in the documentation instead.

DEP0015: fs.readSync legacy String interface#

Type: End-of-Life

The fs.readSync() legacy String interface is deprecated. Use the Buffer API as mentioned in the documentation instead.

DEP0016: GLOBAL/root#

Type: Runtime

The GLOBAL and root aliases for the global property have been deprecated and should no longer be used.

DEP0017: Intl.v8BreakIterator#

Type: End-of-Life

Intl.v8BreakIterator was a non-standard extension and has been removed. See Intl.Segmenter.

DEP0018: Unhandled promise rejections#

Type: Runtime

Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

DEP0019: require('.') resolved outside directory#

Type: Runtime

In certain cases, require('.') may resolve outside the package directory. This behavior is deprecated and will be removed in a future major Node.js release.

DEP0020: Server.connections#

Type: Runtime

The Server.connections property is deprecated. Please use the Server.getConnections() method instead.

DEP0021: Server.listenFD#

Type: Runtime

The Server.listenFD() method is deprecated. Please use Server.listen({fd: <number>}) instead.

DEP0022: os.tmpDir()#

Type: Runtime

The os.tmpDir() API is deprecated. Please use os.tmpdir() instead.

DEP0023: os.getNetworkInterfaces()#

Type: Runtime

The os.getNetworkInterfaces() method is deprecated. Please use the os.networkInterfaces property instead.

DEP0024: REPLServer.prototype.convertToContext()#

Type: End-of-Life

The REPLServer.prototype.convertToContext() API is deprecated and should not be used.

DEP0025: require('sys')#

Type: Runtime

The sys module is deprecated. Please use the util module instead.

DEP0026: util.print()#

Type: Runtime

The util.print() API is deprecated. Please use console.log() instead.

DEP0027: util.puts()#

Type: Runtime

The util.puts() API is deprecated. Please use console.log() instead.

DEP0028: util.debug()#

Type: Runtime

The util.debug() API is deprecated. Please use console.error() instead.

DEP0029: util.error()#

Type: Runtime

The util.error() API is deprecated. Please use console.error() instead.

DEP0030: SlowBuffer#

Type: Documentation-only

The SlowBuffer class has been deprecated. Please use Buffer.allocUnsafeSlow(size) instead.

DEP0031: ecdh.setPublicKey()#

Type: Documentation-only

The ecdh.setPublicKey() method is now deprecated as its inclusion in the API is not useful.

DEP0032: domain module#

Type: Documentation-only

The domain module is deprecated and should not be used.

DEP0033: EventEmitter.listenerCount()#

Type: Documentation-only

The EventEmitter.listenerCount(emitter, eventName) API has been deprecated. Please use emitter.listenerCount(eventName) instead.

DEP0034: fs.exists(path, callback)#

Type: Documentation-only

The fs.exists(path, callback) API has been deprecated. Please use fs.stat() or fs.access() instead.

DEP0035: fs.lchmod(path, mode, callback)#

Type: Documentation-only

The fs.lchmod(path, mode, callback) API has been deprecated.

DEP0036: fs.lchmodSync(path, mode)#

Type: Documentation-only

The fs.lchmodSync(path, mode) API has been deprecated.

DEP0037: fs.lchown(path, uid, gid, callback)#

Type: Documentation-only

The fs.lchown(path, uid, gid, callback) API has been deprecated.

DEP0038: fs.lchownSync(path, uid, gid)#

Type: Documentation-only

The fs.lchownSync(path, uid, gid) API has been deprecated.

DEP0039: require.extensions#

Type: Documentation-only

The require.extensions property has been deprecated.

DEP0040: punycode module#

Type: Documentation-only

The punycode module has been deprecated. Please use a userland alternative instead.

DEP0041: NODE_REPL_HISTORY_FILE environment variable#

Type: End-of-Life

The NODE_REPL_HISTORY_FILE environment variable was removed. Please use NODE_REPL_HISTORY instead.

DEP0042: tls.CryptoStream#

Type: Documentation-only

The tls.CryptoStream class has been deprecated. Please use tls.TLSSocket instead.

DEP0043: tls.SecurePair#

Type: Documentation-only

The tls.SecurePair class has been deprecated. Please use tls.TLSSocket instead.

DEP0044: util.isArray()#

Type: Documentation-only

The util.isArray() API has been deprecated. Please use Array.isArray() instead.

DEP0045: util.isBoolean()#

Type: Documentation-only

The util.isBoolean() API has been deprecated.

DEP0046: util.isBuffer()#

Type: Documentation-only

The util.isBuffer() API has been deprecated. Please use Buffer.isBuffer() instead.

DEP0047: util.isDate()#

Type: Documentation-only

The util.isDate() API has been deprecated.

DEP0048: util.isError()#

Type: Documentation-only

The util.isError() API has been deprecated.

DEP0049: util.isFunction()#

Type: Documentation-only

The util.isFunction() API has been deprecated.

DEP0050: util.isNull()#

Type: Documentation-only

The util.isNull() API has been deprecated.

DEP0051: util.isNullOrUndefined()#

Type: Documentation-only

The util.isNullOrUndefined() API has been deprecated.

DEP0052: util.isNumber()#

Type: Documentation-only

The util.isNumber() API has been deprecated.

DEP0053 util.isObject()#

Type: Documentation-only

The util.isObject() API has been deprecated.

DEP0054: util.isPrimitive()#

Type: Documentation-only

The util.isPrimitive() API has been deprecated.

DEP0055: util.isRegExp()#

Type: Documentation-only

The util.isRegExp() API has been deprecated.

DEP0056: util.isString()#

Type: Documentation-only

The util.isString() API has been deprecated.

DEP0057: util.isSymbol()#

Type: Documentation-only

The util.isSymbol() API has been deprecated.

DEP0058: util.isUndefined()#

Type: Documentation-only

The util.isUndefined() API has been deprecated.

DEP0059: util.log()#

Type: Documentation-only

The util.log() API has been deprecated.

DEP0060: util._extend()#

Type: Documentation-only

The util._extend() API has been deprecated.

DEP0061: fs.SyncWriteStream#

Type: Runtime

The fs.SyncWriteStream class was never intended to be a publicly accessible API. No alternative API is available. Please use a userland alternative.

DEP0062: node --debug#

Type: Runtime

--debug activates the legacy V8 debugger interface, which has been removed as of V8 5.8. It is replaced by Inspector which is activated with --inspect instead.

DEP0063: ServerResponse.prototype.writeHeader()#

Type: Documentation-only

The http module ServerResponse.prototype.writeHeader() API has been deprecated. Please use ServerResponse.prototype.writeHead() instead.

The ServerResponse.prototype.writeHeader() method was never documented as an officially supported API.

DEP0064: tls.createSecurePair()#

Type: Runtime

The tls.createSecurePair() API was deprecated in documentation in Node.js 0.11.3. Users should use tls.Socket instead.

DEP0065: repl.REPL_MODE_MAGIC and NODE_REPL_MODE=magic#

Type: End-of-Life

The repl module's REPL_MODE_MAGIC constant, used for replMode option, has been removed. Its behavior has been functionally identical to that of REPL_MODE_SLOPPY since Node.js 6.0.0, when V8 5.0 was imported. Please use REPL_MODE_SLOPPY instead.

The NODE_REPL_MODE environment variable is used to set the underlying replMode of an interactive node session. Its value, magic, is also removed. Please use sloppy instead.

DEP0066: outgoingMessage._headers, outgoingMessage._headerNames#

Type: Documentation-only

The http module outgoingMessage._headers and outgoingMessage._headerNames properties have been deprecated. Please instead use one of the public methods (e.g. outgoingMessage.getHeader(), outgoingMessage.getHeaders(), outgoingMessage.getHeaderNames(), outgoingMessage.hasHeader(), outgoingMessage.removeHeader(), outgoingMessage.setHeader()) for working with outgoing headers.

The outgoingMessage._headers and outgoingMessage._headerNames properties were never documented as officially supported properties.

DEP0067: OutgoingMessage.prototype._renderHeaders#

Type: Documentation-only

The http module OutgoingMessage.prototype._renderHeaders() API has been deprecated.

The OutgoingMessage.prototype._renderHeaders property was never documented as an officially supported API.

DEP0068: node debug#

Type: Runtime

node debug corresponds to the legacy CLI debugger which has been replaced with a V8-inspector based CLI debugger available through node inspect.

DEP0069: vm.runInDebugContext(string)#

Type: End-of-Life

DebugContext has been removed in V8 and is not available in Node.js 10+.

DebugContext was an experimental API.

DEP0070: async_hooks.currentId()#

Type: End-of-Life

async_hooks.currentId() was renamed to async_hooks.executionAsyncId() for clarity.

This change was made while async_hooks was an experimental API.

DEP0071: async_hooks.triggerId()#

Type: End-of-Life

async_hooks.triggerId() was renamed to async_hooks.triggerAsyncId() for clarity.

This change was made while async_hooks was an experimental API.

DEP0072: async_hooks.AsyncResource.triggerId()#

Type: End-of-Life

async_hooks.AsyncResource.triggerId() was renamed to async_hooks.AsyncResource.triggerAsyncId() for clarity.

This change was made while async_hooks was an experimental API.

DEP0073: Several internal properties of net.Server#

Type: End-of-Life

Accessing several internal, undocumented properties of net.Server instances with inappropriate names has been deprecated.

As the original API was undocumented and not generally useful for non-internal code, no replacement API is provided.

DEP0074: REPLServer.bufferedCommand#

Type: Runtime

The REPLServer.bufferedCommand property was deprecated in favor of REPLServer.clearBufferedCommand().

DEP0075: REPLServer.parseREPLKeyword()#

Type: Runtime

REPLServer.parseREPLKeyword() was removed from userland visibility.

DEP0076: tls.parseCertString()#

Type: Runtime

tls.parseCertString() is a trivial parsing helper that was made public by mistake. This function can usually be replaced with:

const querystring = require('querystring');
querystring.parse(str, '\n', '=');

This function is not completely equivalent to querystring.parse(). One difference is that querystring.parse() does url decoding:

> querystring.parse('%E5%A5%BD=1', '\n', '=');
{ '好': '1' }
> tls.parseCertString('%E5%A5%BD=1');
{ '%E5%A5%BD': '1' }

DEP0077: Module._debug()#

Type: Runtime

Module._debug() has been deprecated.

The Module._debug() function was never documented as an officially supported API.

DEP0078: REPLServer.turnOffEditorMode()#

Type: Runtime

REPLServer.turnOffEditorMode() was removed from userland visibility.

DEP0079: Custom inspection function on Objects via .inspect()#

Type: Runtime

Using a property named inspect on an object to specify a custom inspection function for util.inspect() is deprecated. Use util.inspect.custom instead. For backward compatibility with Node.js prior to version 6.4.0, both may be specified.

DEP0080: path._makeLong()#

Type: Documentation-only

The internal path._makeLong() was not intended for public use. However, userland modules have found it useful. The internal API has been deprecated and replaced with an identical, public path.toNamespacedPath() method.

DEP0081: fs.truncate() using a file descriptor#

Type: Runtime

fs.truncate() fs.truncateSync() usage with a file descriptor has been deprecated. Please use fs.ftruncate() or fs.ftruncateSync() to work with file descriptors.

DEP0082: REPLServer.prototype.memory()#

Type: Runtime

REPLServer.prototype.memory() is only necessary for the internal mechanics of the REPLServer itself. Do not use this function.

DEP0083: Disabling ECDH by setting ecdhCurve to false#

Type: Runtime

The ecdhCurve option to tls.createSecureContext() and tls.TLSSocket could be set to false to disable ECDH entirely on the server only. This mode is deprecated in preparation for migrating to OpenSSL 1.1.0 and consistency with the client. Use the ciphers parameter instead.

DEP0084: requiring bundled internal dependencies#

Type: Runtime

Since Node.js versions 4.4.0 and 5.2.0, several modules only intended for internal usage are mistakenly exposed to user code through require(). These modules are:

  • v8/tools/codemap
  • v8/tools/consarray
  • v8/tools/csvparser
  • v8/tools/logreader
  • v8/tools/profile_view
  • v8/tools/profile
  • v8/tools/SourceMap
  • v8/tools/splaytree
  • v8/tools/tickprocessor-driver
  • v8/tools/tickprocessor
  • node-inspect/lib/_inspect (from 7.6.0)
  • node-inspect/lib/internal/inspect_client (from 7.6.0)
  • node-inspect/lib/internal/inspect_repl (from 7.6.0)

The v8/* modules do not have any exports, and if not imported in a specific order would in fact throw errors. As such there are virtually no legitimate use cases for importing them through require().

On the other hand, node-inspect may be installed locally through a package manager, as it is published on the npm registry under the same name. No source code modification is necessary if that is done.

DEP0085: AsyncHooks Sensitive API#

Type: End-of-Life

The AsyncHooks Sensitive API was never documented and had various minor issues. (See https://github.com/nodejs/node/issues/15572.) Use the AsyncResource API instead.

DEP0086: Remove runInAsyncIdScope#

Type: End-of-Life

runInAsyncIdScope doesn't emit the 'before' or 'after' event and can thus cause a lot of issues. See https://github.com/nodejs/node/issues/14328 for more details.

DEP0089: require('assert')#

Type: Documentation-only

Importing assert directly is not recommended as the exposed functions will use loose equality checks. Use require('assert').strict instead. The API is the same as the legacy assert but it will always use strict equality checks.

DEP0090: Invalid GCM authentication tag lengths#

Type: Runtime

Node.js supports all GCM authentication tag lengths which are accepted by OpenSSL when calling decipher.setAuthTag(). This behavior will change in a future version at which point only authentication tag lengths of 128, 120, 112, 104, 96, 64, and 32 bits will be allowed. Authentication tags whose length is not included in this list will be considered invalid in compliance with NIST SP 800-38D.

DEP0091: crypto.DEFAULT_ENCODING#

Type: Runtime

The crypto.DEFAULT_ENCODING property is deprecated.

DEP0092: Top-level this bound to module.exports#

Type: Documentation-only

Assigning properties to the top-level this as an alternative to module.exports is deprecated. Developers should use exports or module.exports instead.

DEP0093: crypto.fips is deprecated and replaced.#

Type: Documentation-only

The crypto.fips property is deprecated. Please use crypto.setFips() and crypto.getFips() instead.

DEP0094: Using assert.fail() with more than one argument.#

Type: Runtime

Using assert.fail() with more than one argument is deprecated. Use assert.fail() with only one argument or use a different assert module method.

DEP0095: timers.enroll()#

Type: Runtime

timers.enroll() is deprecated. Please use the publicly documented setTimeout() or setInterval() instead.

DEP0096: timers.unenroll()#

Type: Runtime

timers.unenroll() is deprecated. Please use the publicly documented clearTimeout() or clearInterval() instead.

DEP0097: MakeCallback with domain property#

Type: Runtime

Users of MakeCallback that add the domain property to carry context, should start using the async_context variant of MakeCallback or CallbackScope, or the high-level AsyncResource class.

DEP0098: AsyncHooks Embedder AsyncResource.emitBefore and AsyncResource.emitAfter APIs#

Type: Runtime

The embedded API provided by AsyncHooks exposes .emitBefore() and .emitAfter() methods which are very easy to use incorrectly which can lead to unrecoverable errors.

Use asyncResource.runInAsyncScope() API instead which provides a much safer, and more convenient, alternative. See https://github.com/nodejs/node/pull/18513 for more details.

DEP0099: async context-unaware node::MakeCallback C++ APIs#

Type: Compile-time

Certain versions of node::MakeCallback APIs available to native modules are deprecated. Please use the versions of the API that accept an async_context parameter.

DEP0100: process.assert()#

Type: Runtime

process.assert() is deprecated. Please use the assert module instead.

This was never a documented feature.

DEP0101: --with-lttng#

Type: End-of-Life

The --with-lttng compile-time option has been removed.

DEP0102: Using noAssert in Buffer#(read|write) operations.#

Type: End-of-Life

Using the noAssert argument has no functionality anymore. All input is going to be verified, no matter if it is set to true or not. Skipping the verification could lead to hard to find errors and crashes.

DEP0103: process.binding('util').is[...] typechecks#

Type: Documentation-only (supports --pending-deprecation)

Using process.binding() in general should be avoided. The type checking methods in particular can be replaced by using util.types.

DEP0104: process.env string coercion#

Type: Documentation-only (supports --pending-deprecation)

When assigning a non-string property to process.env, the assigned value is implicitly converted to a string. This behavior is deprecated if the assigned value is not a string, boolean, or number. In the future, such assignment may result in a thrown error. Please convert the property to a string before assigning it to process.env.

DEP0105: decipher.finaltol#

Type: Runtime

decipher.finaltol() has never been documented and is currently an alias for decipher.final(). In the future, this API will likely be removed, and it is recommended to use decipher.final() instead.

DEP0106: crypto.createCipher and crypto.createDecipher#

Type: Documentation-only

Using crypto.createCipher() and crypto.createDecipher() should be avoided as they use a weak key derivation function (MD5 with no salt) and static initialization vectors. It is recommended to derive a key using crypto.pbkdf2() and to use crypto.createCipheriv() and crypto.createDecipheriv() to obtain the Cipher and Decipher objects respectively.

DEP0107: tls.convertNPNProtocols()#

Type: Runtime

This was an undocumented helper function not intended for use outside Node.js core and obsoleted by the removal of NPN (Next Protocol Negotiation) support.

DEP0108: zlib.bytesRead#

Type: Documentation-only

Deprecated alias for zlib.bytesWritten. This original name was chosen because it also made sense to interpret the value as the number of bytes read by the engine, but is inconsistent with other streams in Node.js that expose values under these names.