Node.js v14.15.1 文档


目录

命令行选项#

中英对照

Node.js 自带了各种命令行选项。 这些选项开放了内置的调试、执行脚本的多种方式、以及其他有用的运行时选项。

运行 man node 可在一个终端中查看操作手册。

概要#

中英对照

node [options] [V8 options] [script.js | -e "script" | -] [--] [arguments]

node inspect [script.js | -e "script" | <host>:<port>] …

node --v8-options

执行时不带参数,会启动 REPL

关于 node inspect 的更多信息,详见调试器文档。

选项#

中英对照

所有选项(包括 V8 选项)都允许单词用短划线(-)或下划线(_)分隔。 例如, --pending-deprecation 等效于 --pending_deprecation

If an option that takes a single value (such as --max-http-header-size) is passed more than once, then the last passed value is used. Options from the command line take precedence over options passed through the NODE_OPTIONS environment variable.

-#

中英对照

stdin 的别名。 类似于在其他命令行工具中使用 -,这意味着从 stdin 读取脚本,且其余的选项会传给该脚本。

--#

中英对照

指示 node 选项的结束。 其余的参数会被传给脚本。 如果在此之前没有提供脚本的文件名或 eval/print 脚本,则下一个参数会被用作脚本的文件名。

--abort-on-uncaught-exception#

Aborting instead of exiting causes a core file to be generated for post-mortem analysis using a debugger (such as lldb, gdb, and mdb).

If this flag is passed, the behavior can still be set to not abort through process.setUncaughtExceptionCaptureCallback() (and through usage of the domain module that uses it).

--completion-bash#

Print source-able bash completion script for Node.js.

$ node --completion-bash > node_bash_completion
$ source node_bash_completion

--conditions=condition#

稳定性: 1 - 实验

Enable experimental support for custom conditional exports resolution conditions.

Any number of custom string condition names are permitted.

The default Node.js conditions of "node", "default", "import", and "require" will always apply as defined.

--cpu-prof#

稳定性: 1 - 实验

Starts the V8 CPU profiler on start up, and writes the CPU profile to disk before exit.

If --cpu-prof-dir is not specified, the generated profile is placed in the current working directory.

If --cpu-prof-name is not specified, the generated profile is named CPU.${yyyymmdd}.${hhmmss}.${pid}.${tid}.${seq}.cpuprofile.

$ node --cpu-prof index.js
$ ls *.cpuprofile
CPU.20190409.202950.15293.0.0.cpuprofile

--cpu-prof-dir#

稳定性: 1 - 实验

Specify the directory where the CPU profiles generated by --cpu-prof will be placed.

The default value is controlled by the --diagnostic-dir command-line option.

--cpu-prof-interval#

稳定性: 1 - 实验

Specify the sampling interval in microseconds for the CPU profiles generated by --cpu-prof. The default is 1000 microseconds.

--cpu-prof-name#

稳定性: 1 - 实验

Specify the file name of the CPU profile generated by --cpu-prof.

--diagnostic-dir=directory#

Set the directory to which all diagnostic output files are written. Defaults to current working directory.

Affects the default output directory of:

--disable-proto=mode#

Disable the Object.prototype.__proto__ property. If mode is delete, the property is removed entirely. If mode is throw, accesses to the property throw an exception with the code ERR_PROTO_ACCESS.

--disallow-code-generation-from-strings#

Make built-in language features like eval and new Function that generate code from strings throw an exception instead. This does not affect the Node.js vm module.

--enable-fips#

中英对照

启动时启用符合 FIPS 标准的加密。 (需要 Node.js 使用 ./configure --openssl-fips 构建)

--enable-source-maps#

稳定性: 1 - 实验

Enable experimental Source Map v3 support for stack traces.

Currently, overriding Error.prepareStackTrace is ignored when the --enable-source-maps flag is set.

--experimental-import-meta-resolve#

Enable experimental import.meta.resolve() support.

--experimental-json-modules#

Enable experimental JSON support for the ES Module loader.

--experimental-loader=module#

Specify the module of a custom experimental ECMAScript Module loader. module may be either a path to a file, or an ECMAScript Module name.

--experimental-modules#

Enable latest experimental modules features (deprecated).

--experimental-policy#

Use the specified file as a security policy.

--experimental-repl-await#

Enable experimental top-level await keyword support in REPL.

--experimental-specifier-resolution=mode#

Sets the resolution algorithm for resolving ES module specifiers. Valid options are explicit and node.

The default is explicit, which requires providing the full path to a module. The node mode enables support for optional file extensions and the ability to import a directory that has an index file.

See customizing ESM specifier resolution for example usage.

--experimental-vm-modules#

Enable experimental ES Module support in the vm module.

--experimental-wasi-unstable-preview1#

Enable experimental WebAssembly System Interface (WASI) support.

--experimental-wasm-modules#

--force-context-aware#

Disable loading native addons that are not context-aware.

Enable experimental WebAssembly module support.

--force-fips#

中英对照

启动时强制使用符合 FIPS 标准的加密。 (无法通过脚本代码禁用。) (要求同 --enable-fips

--frozen-intrinsics#

稳定性: 1 - 实验

Enable experimental frozen intrinsics like Array and Object.

Support is currently only provided for the root context and no guarantees are currently provided that global.Array is indeed the default intrinsic reference. Code may break under this flag.

--require runs prior to freezing intrinsics in order to allow polyfills to be added.

--heapsnapshot-signal=signal#

Enables a signal handler that causes the Node.js process to write a heap dump when the specified signal is received. signal must be a valid signal name. Disabled by default.

$ node --heapsnapshot-signal=SIGUSR2 index.js &
$ ps aux
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
node         1  5.5  6.1 787252 247004 ?       Ssl  16:43   0:02 node --heapsnapshot-signal=SIGUSR2 index.js
$ kill -USR2 1
$ ls
Heap.20190718.133405.15554.0.001.heapsnapshot

--heap-prof#

稳定性: 1 - 实验

Starts the V8 heap profiler on start up, and writes the heap profile to disk before exit.

If --heap-prof-dir is not specified, the generated profile is placed in the current working directory.

If --heap-prof-name is not specified, the generated profile is named Heap.${yyyymmdd}.${hhmmss}.${pid}.${tid}.${seq}.heapprofile.

$ node --heap-prof index.js
$ ls *.heapprofile
Heap.20190409.202950.15293.0.001.heapprofile

--heap-prof-dir#

稳定性: 1 - 实验

Specify the directory where the heap profiles generated by --heap-prof will be placed.

The default value is controlled by the --diagnostic-dir command-line option.

--heap-prof-interval#

稳定性: 1 - 实验

Specify the average sampling interval in bytes for the heap profiles generated by --heap-prof. The default is 512 * 1024 bytes.

--heap-prof-name#

稳定性: 1 - 实验

Specify the file name of the heap profile generated by --heap-prof.

--icu-data-dir=file#

中英对照

指定 ICU 数据的加载路径。 (覆盖 NODE_ICU_DATA

--input-type=type#

This configures Node.js to interpret string input as CommonJS or as an ES module. String input is input via --eval, --print, or STDIN.

Valid values are "commonjs" and "module". The default is "commonjs".

--inspect-brk[=[host:]port]#

Activate inspector on host:port and break at start of user script. Default host:port is 127.0.0.1:9229.

--inspect-port=[host:]port#

Set the host:port to be used when the inspector is activated. Useful when activating the inspector by sending the SIGUSR1 signal.

Default host is 127.0.0.1.

See the security warning below regarding the host parameter usage.

--inspect[=[host:]port]#

中英对照

host:port 上激活检查器。 默认为 127.0.0.1:9229

V8检查器集成允许 Chrome DevTools 和 IDE 等工具调试和配置 Node.js 实例。 这些工具通过 tcp 端口附加到 Node.js 实例,并使用 Chrome DevTools 协议进行通信.

注意:绑定检查器到公共的“IP:端口”组合是不安全的#

Binding the inspector to a public IP (including 0.0.0.0) with an open port is insecure, as it allows external hosts to connect to the inspector and perform a remote code execution attack.

If specifying a host, make sure that either:

  • The host is not accessible from public networks.
  • A firewall disallows unwanted connections on the port.

More specifically, --inspect=0.0.0.0 is insecure if the port (9229 by default) is not firewall-protected.

See the debugging security implications section for more information.

--inspect-publish-uid=stderr,http#

Specify ways of the inspector web socket url exposure.

By default inspector websocket url is available in stderr and under /json/list endpoint on http://host:port/json/list.

--insecure-http-parser#

Use an insecure HTTP parser that accepts invalid HTTP headers. This may allow interoperability with non-conformant HTTP implementations. It may also allow request smuggling and other HTTP attacks that rely on invalid headers being accepted. Avoid using this option.

--jitless#

Disable runtime allocation of executable memory. This may be required on some platforms for security reasons. It can also reduce attack surface on other platforms, but the performance impact may be severe.

This flag is inherited from V8 and is subject to change upstream. It may disappear in a non-semver-major release.

--max-http-header-size=size#

Specify the maximum size, in bytes, of HTTP headers. Defaults to 16KB.

--napi-modules#

This option is a no-op. It is kept for compatibility.

--no-deprecation#

中英对照

静默弃用的警告。

--no-force-async-hooks-checks#

Disables runtime checks for async_hooks. These will still be enabled dynamically when async_hooks is enabled.

--no-warnings#

中英对照

静默一切进程警告(包括弃用警告)。

--openssl-config=file#

中英对照

启动时加载 OpenSSL 配置文件。 在其他用途中,如果 Node.js 使用 ./configure --openssl-fips 构建,它可以用于启用符合 FIPS 标准的加密。

--pending-deprecation#

Emit pending deprecation warnings.

Pending deprecations are generally identical to a runtime deprecation with the notable exception that they are turned off by default and will not be emitted unless either the --pending-deprecation command-line flag, or the NODE_PENDING_DEPRECATION=1 environment variable, is set. Pending deprecations are used to provide a kind of selective "early warning" mechanism that developers may leverage to detect deprecated API usage.

--policy-integrity=sri#

稳定性: 1 - 实验

Instructs Node.js to error prior to running any code if the policy does not have the specified integrity. It expects a Subresource Integrity string as a parameter.

--preserve-symlinks#

中英对照

当解析和缓存模块时,命令模块加载器保持符号连接。

默认情况下,当 Node.js 从一个被符号连接到另一块磁盘位置的路径加载一个模块时,Node.js 会解引用该连接,并使用模块的真实磁盘的实际路径,作为定位其他依赖模块的标识符和根路径。 大多数情况下,默认行为是可接受的。 但是,当使用符号连接的同行依赖,如下例子所描述的,如果 moduleA 试图引入 moduleB 作为一个同行依赖,默认行为就会抛出异常:

{appDir}
 ├── app
 │   ├── index.js
 │   └── node_modules
 │       ├── moduleA -> {appDir}/moduleA
 │       └── moduleB
 │           ├── index.js
 │           └── package.json
 └── moduleA
     ├── index.js
     └── package.json

--preserve-symlinks 命令行标志命令 Node.js 使用模块的符号路径而不是真实路径,是符号连接的同行依赖能被找到。

注意,使用 --preserve-symlinks 会有其他方面的影响。 比如,如果符号连接的原生模块在依赖树里来自超过一个位置,它们会加载失败。 (Node.js 会将它们视为两个独立的模块,且会试图多次加载模块,造成抛出异常。)

--preserve-symlinks 标志不适用于主模块,它允许 node --preserve-symlinks node_module/.bin/<foo> 工作。 要对主模块应用相同的行为,也可使用 --preserve-symlinks-main

--preserve-symlinks-main#

Instructs the module loader to preserve symbolic links when resolving and caching the main module (require.main).

This flag exists so that the main module can be opted-in to the same behavior that --preserve-symlinks gives to all other imports; they are separate flags, however, for backward compatibility with older Node.js versions.

--preserve-symlinks-main does not imply --preserve-symlinks; use --preserve-symlinks-main in addition to --preserve-symlinks when it is not desirable to follow symlinks before resolving relative paths.

See --preserve-symlinks for more information.

--prof#

Generate V8 profiler output.

--prof-process#

中英对照

处理 V8 分析器的输出,通过使用 V8 选项 --prof 生成。

--redirect-warnings=file#

Write process warnings to the given file instead of printing to stderr. The file will be created if it does not exist, and will be appended to if it does. If an error occurs while attempting to write the warning to the file, the warning will be written to stderr instead.

The file name may be an absolute path. If it is not, the default directory it will be written to is controlled by the --diagnostic-dir command-line option.

--report-compact#

Write reports in a compact format, single-line JSON, more easily consumable by log processing systems than the default multi-line format designed for human consumption.

--report-dir=directory, report-directory=directory#

Location at which the report will be generated.

--report-filename=filename#

Name of the file to which the report will be written.

--report-on-fatalerror#

Enables the report to be triggered on fatal errors (internal errors within the Node.js runtime such as out of memory) that lead to termination of the application. Useful to inspect various diagnostic data elements such as heap, stack, event loop state, resource consumption etc. to reason about the fatal error.

--report-on-signal#

Enables report to be generated upon receiving the specified (or predefined) signal to the running Node.js process. The signal to trigger the report is specified through --report-signal.

--report-signal=signal#

Sets or resets the signal for report generation (not supported on Windows). Default signal is SIGUSR2.

--report-uncaught-exception#

Enables report to be generated on uncaught exceptions. Useful when inspecting the JavaScript stack in conjunction with native stack and other runtime environment data.

--throw-deprecation#

中英对照

抛出弃用的错误。

--title=title#

Set process.title on startup.

--tls-cipher-list=list#

中英对照

指定备用的默认 TLS 加密列表。 需要 Node.js 被构建为支持加密(默认)。

--tls-keylog=file#

Log TLS key material to a file. The key material is in NSS SSLKEYLOGFILE format and can be used by software (such as Wireshark) to decrypt the TLS traffic.

--tls-max-v1.2#

Set tls.DEFAULT_MAX_VERSION to 'TLSv1.2'. Use to disable support for TLSv1.3.

--tls-max-v1.3#

Set default tls.DEFAULT_MAX_VERSION to 'TLSv1.3'. Use to enable support for TLSv1.3.

--tls-min-v1.0#

Set default tls.DEFAULT_MIN_VERSION to 'TLSv1'. Use for compatibility with old TLS clients or servers.

--tls-min-v1.1#

Set default tls.DEFAULT_MIN_VERSION to 'TLSv1.1'. Use for compatibility with old TLS clients or servers.

--tls-min-v1.2#

Set default tls.DEFAULT_MIN_VERSION to 'TLSv1.2'. This is the default for 12.x and later, but the option is supported for compatibility with older Node.js versions.

--tls-min-v1.3#

Set default tls.DEFAULT_MIN_VERSION to 'TLSv1.3'. Use to disable support for TLSv1.2, which is not as secure as TLSv1.3.

--trace-atomics-wait#

Print short summaries of calls to Atomics.wait() to stderr. The output could look like this:

(node:15701) [Thread 0] Atomics.wait(<address> + 0, 1, inf) started
(node:15701) [Thread 0] Atomics.wait(<address> + 0, 1, inf) did not wait because the values mismatched
(node:15701) [Thread 0] Atomics.wait(<address> + 0, 0, 10) started
(node:15701) [Thread 0] Atomics.wait(<address> + 0, 0, 10) timed out
(node:15701) [Thread 0] Atomics.wait(<address> + 4, 0, inf) started
(node:15701) [Thread 1] Atomics.wait(<address> + 4, -1, inf) started
(node:15701) [Thread 0] Atomics.wait(<address> + 4, 0, inf) was woken up by another thread
(node:15701) [Thread 1] Atomics.wait(<address> + 4, -1, inf) was woken up by another thread

The fields here correspond to:

  • The thread id as given by worker_threads.threadId
  • The base address of the SharedArrayBuffer in question, as well as the byte offset corresponding to the index passed to Atomics.wait()
  • The expected value that was passed to Atomics.wait()
  • The timeout passed to Atomics.wait

--trace-deprecation#

中英对照

打印弃用的堆栈跟踪。

--trace-event-categories#

A comma separated list of categories that should be traced when trace event tracing is enabled using --trace-events-enabled.

--trace-event-file-pattern#

Template string specifying the filepath for the trace event data, it supports ${rotation} and ${pid}.

--trace-events-enabled#

Enables the collection of trace event tracing information.

--trace-exit#

Prints a stack trace whenever an environment is exited proactively, i.e. invoking process.exit().

--trace-sigint#

Prints a stack trace on SIGINT.

--trace-sync-io#

中英对照

每当事件循环的第一帧之后检测到同步 I/O 时,打印堆栈跟踪。

--trace-tls#

Prints TLS packet trace information to stderr. This can be used to debug TLS connection problems.

--trace-uncaught#

Print stack traces for uncaught exceptions; usually, the stack trace associated with the creation of an Error is printed, whereas this makes Node.js also print the stack trace associated with throwing the value (which does not need to be an Error instance).

Enabling this option may affect garbage collection behavior negatively.

--trace-warnings#

中英对照

打印进程警告的堆栈跟踪(包括弃用警告)。

--track-heap-objects#

中英对照

为堆快照追踪堆栈对象的分配。

--unhandled-rejections=mode#

By default all unhandled rejections trigger a warning plus a deprecation warning for the very first unhandled rejection in case no unhandledRejection hook is used.

Using this flag allows to change what should happen when an unhandled rejection occurs. One of the following modes can be chosen:

  • throw: Emit unhandledRejection. If this hook is not set, raise the unhandled rejection as an uncaught exception.
  • strict: Raise the unhandled rejection as an uncaught exception.
  • warn: Always trigger a warning, no matter if the unhandledRejection hook is set or not but do not print the deprecation warning.
  • warn-with-error-code: Emit unhandledRejection. If this hook is not set, trigger a warning, and set the process exit code to 1.
  • none: Silence all warnings.

--use-bundled-ca, --use-openssl-ca#

Use bundled Mozilla CA store as supplied by current Node.js version or use OpenSSL's default CA store. The default store is selectable at build-time.

The bundled CA store, as supplied by Node.js, is a snapshot of Mozilla CA store that is fixed at release time. It is identical on all supported platforms.

Using OpenSSL store allows for external modifications of the store. For most Linux and BSD distributions, this store is maintained by the distribution maintainers and system administrators. OpenSSL CA store location is dependent on configuration of the OpenSSL library but this can be altered at runtime using environment variables.

See SSL_CERT_DIR and SSL_CERT_FILE.

--use-largepages=mode#

Re-map the Node.js static code to large memory pages at startup. If supported on the target system, this will cause the Node.js static code to be moved onto 2 MiB pages instead of 4 KiB pages.

The following values are valid for mode:

  • off: No mapping will be attempted. This is the default.
  • on: If supported by the OS, mapping will be attempted. Failure to map will be ignored and a message will be printed to standard error.
  • silent: If supported by the OS, mapping will be attempted. Failure to map will be ignored and will not be reported.

--v8-options#

中英对照

打印 V8 命令行选项。

--v8-pool-size=num#

Set V8's thread pool size which will be used to allocate background jobs.

If set to 0 then V8 will choose an appropriate size of the thread pool based on the number of online processors.

If the value provided is larger than V8's maximum, then the largest value will be chosen.

--zero-fill-buffers#

中英对照

自动用 0 填充所有新分配的 BufferSlowBuffer 实例。

-c, --check#

中英对照

在不执行的情况下,对脚本进行语法检查。

-e, --eval "script"#

中英对照

把跟随的参数作为 JavaScript 来执行。 在 REPL 中预定义的模块也可以在 script 中使用。

在 Windows 上,使用 cmd.exe 单引号将会无法正常工作,因为它只识别双引号 "。 在 Powershell 或 Git bash 中, '" 都可用。

-h, --help#

中英对照

打印 node 的命令行选项。 此选项的输出不如本文档详细。

-i, --interactive#

中英对照

打开 REPL,即使 stdin 看起来不像终端。

-p, --print "script"#

中英对照

-e 相同,但会打印结果。

-r, --require module#

中英对照

在启动时预加载指定的模块。

遵循 require() 的模块解析规则。 module 可以是一个文件的路径,或一个 node 模块名称。

-v, --version#

中英对照

打印 node 的版本号。

环境变量#

NODE_DEBUG=module[,…]#

中英对照

',' 分隔的应该打印调试信息的核心模块列表。

NODE_DEBUG_NATIVE=module[,…]#

','-separated list of core C++ modules that should print debug information.

NODE_DISABLE_COLORS=1#

中英对照

当有设置时,不会在 REPL 中使用颜色。

NODE_EXTRA_CA_CERTS=file#

中英对照

当设置了此选项时,根 CA 证书(如 VeriSign)会被 file 指定的证书扩展。 文件应该包括一个或多个可信的 PEM 格式的证书。 如果文件丢失或有缺陷,则 process.emitWarning() 会触发一个消息。

当一个 TLS 或 HTTPS 的客户端或服务器的 ca 选项的属性被显式地指定时,则指定的证书不会被使用。

node 以 setuid root 运行或设置了 Linux 文件功能时,将会忽略此环境变量。

NODE_ICU_DATA=file#

中英对照

ICU(Intl 对象)数据的数据路径。 当使用 small-icu 编译时,扩展链接的数据。

NODE_NO_WARNINGS=1#

When set to 1, process warnings are silenced.

NODE_OPTIONS=options...#

A space-separated list of command-line options. options... are interpreted before command-line options, so command-line options will override or compound after anything in options.... Node.js will exit with an error if an option that is not allowed in the environment is used, such as -p or a script file.

If an option value contains a space, it can be escaped using double quotes:

NODE_OPTIONS='--require "./my path/file.js"'

A singleton flag passed as a command-line option will override the same flag passed into NODE_OPTIONS:

# The inspector will be available on port 5555
NODE_OPTIONS='--inspect=localhost:4444' node --inspect=localhost:5555

A flag that can be passed multiple times will be treated as if its NODE_OPTIONS instances were passed first, and then its command-line instances afterwards:

NODE_OPTIONS='--require "./a.js"' node --require "./b.js"
# is equivalent to:
node --require "./a.js" --require "./b.js"

Node.js options that are allowed are:

  • --conditions
  • --diagnostic-dir
  • --disable-proto
  • --enable-fips
  • --enable-source-maps
  • --experimental-import-meta-resolve
  • --experimental-json-modules
  • --experimental-loader
  • --experimental-modules
  • --experimental-policy
  • --experimental-repl-await
  • --experimental-specifier-resolution
  • --experimental-top-level-await
  • --experimental-vm-modules
  • --experimental-wasi-unstable-preview1
  • --experimental-wasm-modules
  • --force-context-aware
  • --force-fips
  • --frozen-intrinsics
  • --heapsnapshot-signal
  • --http-parser
  • --icu-data-dir
  • --input-type
  • --insecure-http-parser
  • --inspect-brk
  • --inspect-port, --debug-port
  • --inspect-publish-uid
  • --inspect
  • --max-http-header-size
  • --napi-modules
  • --no-deprecation
  • --no-force-async-hooks-checks
  • --no-warnings
  • --openssl-config
  • --pending-deprecation
  • --policy-integrity
  • --preserve-symlinks-main
  • --preserve-symlinks
  • --prof-process
  • --redirect-warnings
  • --report-compact
  • --report-dir, --report-directory
  • --report-filename
  • --report-on-fatalerror
  • --report-on-signal
  • --report-signal
  • --report-uncaught-exception
  • --require, -r
  • --throw-deprecation
  • --title
  • --tls-cipher-list
  • --tls-keylog
  • --tls-max-v1.2
  • --tls-max-v1.3
  • --tls-min-v1.0
  • --tls-min-v1.1
  • --tls-min-v1.2
  • --tls-min-v1.3
  • --trace-atomics-wait
  • --trace-deprecation
  • --trace-event-categories
  • --trace-event-file-pattern
  • --trace-events-enabled
  • --trace-exit
  • --trace-sigint
  • --trace-sync-io
  • --trace-tls
  • --trace-uncaught
  • --trace-warnings
  • --track-heap-objects
  • --unhandled-rejections
  • --use-bundled-ca
  • --use-largepages
  • --use-openssl-ca
  • --v8-pool-size
  • --zero-fill-buffers

V8 options that are allowed are:

  • --abort-on-uncaught-exception
  • --disallow-code-generation-from-strings
  • --huge-max-old-generation-size
  • --interpreted-frames-native-stack
  • --jitless
  • --max-old-space-size
  • --perf-basic-prof-only-functions
  • --perf-basic-prof
  • --perf-prof-unwinding-info
  • --perf-prof
  • --stack-trace-limit

--perf-basic-prof-only-functions, --perf-basic-prof, --perf-prof-unwinding-info, and --perf-prof are only available on Linux.

NODE_PATH=path[:…]#

中英对照

':' 分隔的有模块搜索路径作前缀的目录列表。

在 Windows 中,列表是用 ';' 分隔的。

NODE_PENDING_DEPRECATION=1#

When set to 1, emit pending deprecation warnings.

Pending deprecations are generally identical to a runtime deprecation with the notable exception that they are turned off by default and will not be emitted unless either the --pending-deprecation command-line flag, or the NODE_PENDING_DEPRECATION=1 environment variable, is set. Pending deprecations are used to provide a kind of selective "early warning" mechanism that developers may leverage to detect deprecated API usage.

NODE_PENDING_PIPE_INSTANCES=instances#

Set the number of pending pipe instance handles when the pipe server is waiting for connections. This setting applies to Windows only.

NODE_PRESERVE_SYMLINKS=1#

When set to 1, instructs the module loader to preserve symbolic links when resolving and caching modules.

NODE_REDIRECT_WARNINGS=file#

When set, process warnings will be emitted to the given file instead of printing to stderr. The file will be created if it does not exist, and will be appended to if it does. If an error occurs while attempting to write the warning to the file, the warning will be written to stderr instead. This is equivalent to using the --redirect-warnings=file command-line flag.

NODE_REPL_HISTORY=file#

中英对照

用于存储持久性的 REPL 历史记录的文件的路径。 默认路径是 ~/.node_repl_history,可被该变量覆盖。 将值设为空字符串(''' ')会禁用持久性的 REPL 历史记录。

NODE_REPL_EXTERNAL_MODULE=file#

Path to a Node.js module which will be loaded in place of the built-in REPL. Overriding this value to an empty string ('') will use the built-in REPL.

NODE_SKIP_PLATFORM_CHECK=value#

If value equals '1', the check for a supported platform is skipped during Node.js startup. Node.js might not execute correctly. Any issues encountered on unsupported platforms will not be fixed.

NODE_TLS_REJECT_UNAUTHORIZED=value#

If value equals '0', certificate validation is disabled for TLS connections. This makes TLS, and HTTPS by extension, insecure. The use of this environment variable is strongly discouraged.

NODE_V8_COVERAGE=dir#

When set, Node.js will begin outputting V8 JavaScript code coverage and Source Map data to the directory provided as an argument (coverage information is written as JSON to files with a coverage prefix).

NODE_V8_COVERAGE will automatically propagate to subprocesses, making it easier to instrument applications that call the child_process.spawn() family of functions. NODE_V8_COVERAGE can be set to an empty string, to prevent propagation.

覆盖范围的输出#

Coverage is output as an array of ScriptCoverage objects on the top-level key result:

{
  "result": [
    {
      "scriptId": "67",
      "url": "internal/tty.js",
      "functions": []
    }
  ]
}

源码映射的缓存#

稳定性: 1 - 实验

If found, source map data is appended to the top-level key source-map-cache on the JSON coverage object.

source-map-cache is an object with keys representing the files source maps were extracted from, and values which include the raw source-map URL (in the key url), the parsed Source Map v3 information (in the key data), and the line lengths of the source file (in the key lineLengths).

{
  "result": [
    {
      "scriptId": "68",
      "url": "file:///absolute/path/to/source.js",
      "functions": []
    }
  ],
  "source-map-cache": {
    "file:///absolute/path/to/source.js": {
      "url": "./path-to-map.json",
      "data": {
        "version": 3,
        "sources": [
          "file:///absolute/path/to/original.js"
        ],
        "names": [
          "Foo",
          "console",
          "info"
        ],
        "mappings": "MAAMA,IACJC,YAAaC",
        "sourceRoot": "./"
      },
      "lineLengths": [
        13,
        62,
        38,
        27
      ]
    }
  }
}

OPENSSL_CONF=file#

Load an OpenSSL configuration file on startup. Among other uses, this can be used to enable FIPS-compliant crypto if Node.js is built with ./configure --openssl-fips.

If the --openssl-config command-line option is used, the environment variable is ignored.

SSL_CERT_DIR=dir#

If --use-openssl-ca is enabled, this overrides and sets OpenSSL's directory containing trusted certificates.

Be aware that unless the child environment is explicitly set, this environment variable will be inherited by any child processes, and if they use OpenSSL, it may cause them to trust the same CAs as node.

SSL_CERT_FILE=file#

If --use-openssl-ca is enabled, this overrides and sets OpenSSL's file containing trusted certificates.

Be aware that unless the child environment is explicitly set, this environment variable will be inherited by any child processes, and if they use OpenSSL, it may cause them to trust the same CAs as node.

UV_THREADPOOL_SIZE=size#

Set the number of threads used in libuv's threadpool to size threads.

Asynchronous system APIs are used by Node.js whenever possible, but where they do not exist, libuv's threadpool is used to create asynchronous node APIs based on synchronous system APIs. Node.js APIs that use the threadpool are:

  • all fs APIs, other than the file watcher APIs and those that are explicitly synchronous
  • asynchronous crypto APIs such as crypto.pbkdf2(), crypto.scrypt(), crypto.randomBytes(), crypto.randomFill(), crypto.generateKeyPair()
  • dns.lookup()
  • all zlib APIs, other than those that are explicitly synchronous

Because libuv's threadpool has a fixed size, it means that if for whatever reason any of these APIs takes a long time, other (seemingly unrelated) APIs that run in libuv's threadpool will experience degraded performance. In order to mitigate this issue, one potential solution is to increase the size of libuv's threadpool by setting the 'UV_THREADPOOL_SIZE' environment variable to a value greater than 4 (its current default value). For more information, see the libuv threadpool documentation.

有用的 V8 选项#

V8 has its own set of CLI options. Any V8 CLI option that is provided to node will be passed on to V8 to handle. V8's options have no stability guarantee. The V8 team themselves don't consider them to be part of their formal API, and reserve the right to change them at any time. Likewise, they are not covered by the Node.js stability guarantees. Many of the V8 options are of interest only to V8 developers. Despite this, there is a small set of V8 options that are widely applicable to Node.js, and they are documented here:

--max-old-space-size=SIZE (in megabytes)#

Sets the max memory size of V8's old memory section. As memory consumption approaches the limit, V8 will spend more time on garbage collection in an effort to free unused memory.

On a machine with 2GB of memory, consider setting this to 1536 (1.5GB) to leave some memory for other uses and avoid swapping.

$ node --max-old-space-size=1536 index.js