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# Command-line API
<!--introduced_in=v5.9.1-->
<!--type=misc-->
Node.js comes with a variety of CLI options. These options expose built-in
debugging, multiple ways to execute scripts, and other helpful runtime options.
To view this documentation as a manual page in a terminal, run `man node`.
## Synopsis
`node [options] [V8 options] [<program-entry-point> | -e "script" | -] [--] [arguments]`
`node inspect [<program-entry-point> | -e "script" | <host>:<port>] β¦`
`node --v8-options`
Execute without arguments to start the [REPL][].
For more info about `node inspect`, see the [debugger][] documentation.
## Program entry point
The program entry point is a specifier-like string. If the string is not an
absolute path, it's resolved as a relative path from the current working
directory. That path is then resolved by [CommonJS][] module loader, or by the
[ES module loader][Modules loaders] if [`--experimental-default-type=module`][]
is passed. If no corresponding file is found, an error is thrown.
If a file is found, its path will be passed to the
[ES module loader][Modules loaders] under any of the following conditions:
* The program was started with a command-line flag that forces the entry
point to be loaded with ECMAScript module loader, such as `--import` or
[`--experimental-default-type=module`][].
* The file has an `.mjs` extension.
* The file does not have a `.cjs` extension, and the nearest parent
`package.json` file contains a top-level [`"type"`][] field with a value of
`"module"`.
Otherwise, the file is loaded using the CommonJS module loader. See
[Modules loaders][] for more details.
### ECMAScript modules loader entry point caveat
When loading, the [ES module loader][Modules loaders] loads the program
entry point, the `node` command will accept as input only files with `.js`,
`.mjs`, or `.cjs` extensions; with `.wasm` extensions when
[`--experimental-wasm-modules`][] is enabled; and with no extension when
[`--experimental-default-type=module`][] is passed.
## Options
<!-- YAML
changes:
- version: v10.12.0
pr-url: https://github.com/nodejs/node/pull/23020
description: Underscores instead of dashes are now allowed for
Node.js options as well, in addition to V8 options.
-->
All options, including V8 options, allow words to be separated by both
dashes (`-`) or underscores (`_`). For example, `--pending-deprecation` is
equivalent to `--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.
### `-`
<!-- YAML
added: v8.0.0
-->
Alias for stdin. Analogous to the use of `-` in other command-line utilities,
meaning that the script is read from stdin, and the rest of the options
are passed to that script.
### `--`
<!-- YAML
added: v6.11.0
-->
Indicate the end of node options. Pass the rest of the arguments to the script.
If no script filename or eval/print script is supplied prior to this, then
the next argument is used as a script filename.
### `--abort-on-uncaught-exception`
<!-- YAML
added: v0.10.8
-->
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
`node:domain` module that uses it).
### `--allow-addons`
<!-- YAML
added:
- v21.6.0
- v20.12.0
-->
> Stability: 1.1 - Active development
When using the [Permission Model][], the process will not be able to use
native addons by default.
Attempts to do so will throw an `ERR_DLOPEN_DISABLED` unless the
user explicitly passes the `--allow-addons` flag when starting Node.js.
Example:
```cjs
// Attempt to require an native addon
require('nodejs-addon-example');
```
```console
$ node --experimental-permission --allow-fs-read=* index.js
node:internal/modules/cjs/loader:1319
return process.dlopen(module, path.toNamespacedPath(filename));
^
Error: Cannot load native addon because loading addons is disabled.
at Module._extensions..node (node:internal/modules/cjs/loader:1319:18)
at Module.load (node:internal/modules/cjs/loader:1091:32)
at Module._load (node:internal/modules/cjs/loader:938:12)
at Module.require (node:internal/modules/cjs/loader:1115:19)
at require (node:internal/modules/helpers:130:18)
at Object.<anonymous> (/home/index.js:1:15)
at Module._compile (node:internal/modules/cjs/loader:1233:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1287:10)
at Module.load (node:internal/modules/cjs/loader:1091:32)
at Module._load (node:internal/modules/cjs/loader:938:12) {
code: 'ERR_DLOPEN_DISABLED'
}
```
### `--allow-child-process`
<!-- YAML
added: v20.0.0
-->
> Stability: 1.1 - Active development
When using the [Permission Model][], the process will not be able to spawn any
child process by default.
Attempts to do so will throw an `ERR_ACCESS_DENIED` unless the
user explicitly passes the `--allow-child-process` flag when starting Node.js.
Example:
```js
const childProcess = require('node:child_process');
// Attempt to bypass the permission
childProcess.spawn('node', ['-e', 'require("fs").writeFileSync("/new-file", "example")']);
```
```console
$ node --experimental-permission --allow-fs-read=* index.js
node:internal/child_process:388
const err = this._handle.spawn(options);
^
Error: Access to this API has been restricted
at ChildProcess.spawn (node:internal/child_process:388:28)
at Object.spawn (node:child_process:723:9)
at Object.<anonymous> (/home/index.js:3:14)
at Module._compile (node:internal/modules/cjs/loader:1120:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1174:10)
at Module.load (node:internal/modules/cjs/loader:998:32)
at Module._load (node:internal/modules/cjs/loader:839:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:17:47 {
code: 'ERR_ACCESS_DENIED',
permission: 'ChildProcess'
}
```
### `--allow-fs-read`
<!-- YAML
added: v20.0.0
changes:
- version: v20.7.0
pr-url: https://github.com/nodejs/node/pull/49047
description: Paths delimited by comma (`,`) are no longer allowed.
-->
> Stability: 1.1 - Active development
This flag configures file system read permissions using
the [Permission Model][].
The valid arguments for the `--allow-fs-read` flag are:
* `*` - To allow all `FileSystemRead` operations.
* Multiple paths can be allowed using multiple `--allow-fs-read` flags.
Example `--allow-fs-read=/folder1/ --allow-fs-read=/folder1/`
Paths delimited by comma (`,`) are no longer allowed.
When passing a single flag with a comma a warning will be displayed.
Examples can be found in the [File System Permissions][] documentation.
Relative paths are NOT yet supported by the CLI flag.
The initializer module also needs to be allowed. Consider the following example:
```console
$ node --experimental-permission t.js
node:internal/modules/cjs/loader:162
const result = internalModuleStat(filename);
^
Error: Access to this API has been restricted
at stat (node:internal/modules/cjs/loader:162:18)
at Module._findPath (node:internal/modules/cjs/loader:640:16)
at resolveMainPath (node:internal/modules/run_main:15:25)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:53:24)
at node:internal/main/run_main_module:23:47 {
code: 'ERR_ACCESS_DENIED',
permission: 'FileSystemRead',
resource: '/Users/rafaelgss/repos/os/node/t.js'
}
```
The process needs to have access to the `index.js` module:
```bash
node --experimental-permission --allow-fs-read=/path/to/index.js index.js
```
### `--allow-fs-write`
<!-- YAML
added: v20.0.0
changes:
- version: v20.7.0
pr-url: https://github.com/nodejs/node/pull/49047
description: Paths delimited by comma (`,`) are no longer allowed.
-->
> Stability: 1.1 - Active development
This flag configures file system write permissions using
the [Permission Model][].
The valid arguments for the `--allow-fs-write` flag are:
* `*` - To allow all `FileSystemWrite` operations.
* Multiple paths can be allowed using multiple `--allow-fs-read` flags.
Example `--allow-fs-read=/folder1/ --allow-fs-read=/folder1/`
Paths delimited by comma (`,`) are no longer allowed.
When passing a single flag with a comma a warning will be displayed.
Examples can be found in the [File System Permissions][] documentation.
Relative paths are NOT supported through the CLI flag.
### `--allow-wasi`
<!-- YAML
added: v22.3.0
-->
> Stability: 1.1 - Active development
When using the [Permission Model][], the process will not be capable of creating
any WASI instances by default.
For security reasons, the call will throw an `ERR_ACCESS_DENIED` unless the
user explicitly passes the flag `--allow-wasi` in the main Node.js process.
Example:
```js
const { WASI } = require('node:wasi');
// Attempt to bypass the permission
new WASI({
version: 'preview1',
// Attempt to mount the whole filesystem
preopens: {
'/': '/',
},
});
```
```console
$ node --experimental-permission --allow-fs-read=* index.js
node:wasi:99
const wrap = new _WASI(args, env, preopens, stdio);
^
Error: Access to this API has been restricted
at new WASI (node:wasi:99:18)
at Object.<anonymous> (/home/index.js:3:1)
at Module._compile (node:internal/modules/cjs/loader:1476:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1555:10)
at Module.load (node:internal/modules/cjs/loader:1288:32)
at Module._load (node:internal/modules/cjs/loader:1104:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:191:14)
at node:internal/main/run_main_module:30:49 {
code: 'ERR_ACCESS_DENIED',
permission: 'WASI',
}
```
### `--allow-worker`
<!-- YAML
added: v20.0.0
-->
> Stability: 1.1 - Active development
When using the [Permission Model][], the process will not be able to create any
worker threads by default.
For security reasons, the call will throw an `ERR_ACCESS_DENIED` unless the
user explicitly pass the flag `--allow-worker` in the main Node.js process.
Example:
```js
const { Worker } = require('node:worker_threads');
// Attempt to bypass the permission
new Worker(__filename);
```
```console
$ node --experimental-permission --allow-fs-read=* index.js
node:internal/worker:188
this[kHandle] = new WorkerImpl(url,
^
Error: Access to this API has been restricted
at new Worker (node:internal/worker:188:21)
at Object.<anonymous> (/home/index.js.js:3:1)
at Module._compile (node:internal/modules/cjs/loader:1120:14)
at Module._extensions..js (node:internal/modules/cjs/loader:1174:10)
at Module.load (node:internal/modules/cjs/loader:998:32)
at Module._load (node:internal/modules/cjs/loader:839:12)
at Function.executeUserEntryPoint [as runMain] (node:internal/modules/run_main:81:12)
at node:internal/main/run_main_module:17:47 {
code: 'ERR_ACCESS_DENIED',
permission: 'WorkerThreads'
}
```
### `--build-snapshot`
<!-- YAML
added: v18.8.0
-->
> Stability: 1 - Experimental
Generates a snapshot blob when the process exits and writes it to
disk, which can be loaded later with `--snapshot-blob`.
When building the snapshot, if `--snapshot-blob` is not specified,
the generated blob will be written, by default, to `snapshot.blob`
in the current working directory. Otherwise it will be written to
the path specified by `--snapshot-blob`.
```console
$ echo "globalThis.foo = 'I am from the snapshot'" > snapshot.js
# Run snapshot.js to initialize the application and snapshot the
# state of it into snapshot.blob.
$ node --snapshot-blob snapshot.blob --build-snapshot snapshot.js
$ echo "console.log(globalThis.foo)" > index.js
# Load the generated snapshot and start the application from index.js.
$ node --snapshot-blob snapshot.blob index.js
I am from the snapshot
```
The [`v8.startupSnapshot` API][] can be used to specify an entry point at
snapshot building time, thus avoiding the need of an additional entry
script at deserialization time:
```console
$ echo "require('v8').startupSnapshot.setDeserializeMainFunction(() => console.log('I am from the snapshot'))" > snapshot.js
$ node --snapshot-blob snapshot.blob --build-snapshot snapshot.js
$ node --snapshot-blob snapshot.blob
I am from the snapshot
```
For more information, check out the [`v8.startupSnapshot` API][] documentation.
Currently the support for run-time snapshot is experimental in that:
1. User-land modules are not yet supported in the snapshot, so only
one single file can be snapshotted. Users can bundle their applications
into a single script with their bundler of choice before building
a snapshot, however.
2. Only a subset of the built-in modules work in the snapshot, though the
Node.js core test suite checks that a few fairly complex applications
can be snapshotted. Support for more modules are being added. If any
crashes or buggy behaviors occur when building a snapshot, please file
a report in the [Node.js issue tracker][] and link to it in the
[tracking issue for user-land snapshots][].
### `--build-snapshot-config`
<!-- YAML
added:
- v21.6.0
- v20.12.0
-->
> Stability: 1 - Experimental
Specifies the path to a JSON configuration file which configures snapshot
creation behavior.
The following options are currently supported:
* `builder` {string} Required. Provides the name to the script that is executed
before building the snapshot, as if [`--build-snapshot`][] had been passed
with `builder` as the main script name.
* `withoutCodeCache` {boolean} Optional. Including the code cache reduces the
time spent on compiling functions included in the snapshot at the expense
of a bigger snapshot size and potentially breaking portability of the
snapshot.
When using this flag, additional script files provided on the command line will
not be executed and instead be interpreted as regular command line arguments.
### `-c`, `--check`
<!-- YAML
added:
- v5.0.0
- v4.2.0
changes:
- version: v10.0.0
pr-url: https://github.com/nodejs/node/pull/19600
description: The `--require` option is now supported when checking a file.
-->
Syntax check the script without executing.
### `--completion-bash`
<!-- YAML
added: v10.12.0
-->
Print source-able bash completion script for Node.js.
```bash
node --completion-bash > node_bash_completion
source node_bash_completion
```
### `-C condition`, `--conditions=condition`
<!-- YAML
added:
- v14.9.0
- v12.19.0
-->
> Stability: 1 - Experimental
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.
For example, to run a module with "development" resolutions:
```bash
node -C development app.js
```
### `--cpu-prof`
<!-- YAML
added: v12.0.0
changes:
- version:
- REPLACEME
pr-url: https://github.com/nodejs/node/pull/53343
description: The `--cpu-prof` flags are now stable.
-->
> Stability: 2 - Stable
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`.
```console
$ node --cpu-prof index.js
$ ls *.cpuprofile
CPU.20190409.202950.15293.0.0.cpuprofile
```
### `--cpu-prof-dir`
<!-- YAML
added: v12.0.0
changes:
- version:
- REPLACEME
pr-url: https://github.com/nodejs/node/pull/53343
description: The `--cpu-prof` flags are now stable.
-->
> Stability: 2 - Stable
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`
<!-- YAML
added: v12.2.0
changes:
- version:
- REPLACEME
pr-url: https://github.com/nodejs/node/pull/53343
description: The `--cpu-prof` flags are now stable.
-->
> Stability: 2 - Stable
Specify the sampling interval in microseconds for the CPU profiles generated
by `--cpu-prof`. The default is 1000 microseconds.
### `--cpu-prof-name`
<!-- YAML
added: v12.0.0
changes:
- version:
- REPLACEME
pr-url: https://github.com/nodejs/node/pull/53343
description: The `--cpu-prof` flags are now stable.
-->
> Stability: 2 - Stable
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:
* [`--cpu-prof-dir`][]
* [`--heap-prof-dir`][]
* [`--redirect-warnings`][]
### `--disable-warning=code-or-type`
> Stability: 1.1 - Active development
<!-- YAML
added:
- v21.3.0
- v20.11.0
-->
Disable specific process warnings by `code` or `type`.
Warnings emitted from [`process.emitWarning()`][emit_warning] may contain a
`code` and a `type`. This option will not-emit warnings that have a matching
`code` or `type`.
List of [deprecation warnings][].
The Node.js core warning types are: `DeprecationWarning` and
`ExperimentalWarning`
For example, the following script will not emit
[DEP0025 `require('node:sys')`][DEP0025 warning] when executed with
`node --disable-warning=DEP0025`:
```mjs
import sys from 'node:sys';
```
```cjs
const sys = require('node:sys');
```
For example, the following script will emit the
[DEP0025 `require('node:sys')`][DEP0025 warning], but not any Experimental
Warnings (such as
[ExperimentalWarning: `vm.measureMemory` is an experimental feature][]
in <=v21) when executed with `node --disable-warning=ExperimentalWarning`:
```mjs
import sys from 'node:sys';
import vm from 'node:vm';
vm.measureMemory();
```
```cjs
const sys = require('node:sys');
const vm = require('node:vm');
vm.measureMemory();
```
### `--disable-wasm-trap-handler`
<!-- YAML
added: v22.2.0
-->
By default, Node.js enables trap-handler-based WebAssembly bound
checks. As a result, V8 does not need to insert inline bound checks
int the code compiled from WebAssembly which may speedup WebAssembly
execution significantly, but this optimization requires allocating
a big virtual memory cage (currently 10GB). If the Node.js process
does not have access to a large enough virtual memory address space
due to system configurations or hardware limitations, users won't
be able to run any WebAssembly that involves allocation in this
virtual memory cage and will see an out-of-memory error.
```console
$ ulimit -v 5000000
$ node -p "new WebAssembly.Memory({ initial: 10, maximum: 100 });"
[eval]:1
new WebAssembly.Memory({ initial: 10, maximum: 100 });
^
RangeError: WebAssembly.Memory(): could not allocate memory
at [eval]:1:1
at runScriptInThisContext (node:internal/vm:209:10)
at node:internal/process/execution:118:14
at [eval]-wrapper:6:24
at runScript (node:internal/process/execution:101:62)
at evalScript (node:internal/process/execution:136:3)
at node:internal/main/eval_string:49:3
```
`--disable-wasm-trap-handler` disables this optimization so that
users can at least run WebAssembly (with less optimal performance)
when the virtual memory address space available to their Node.js
process is lower than what the V8 WebAssembly memory cage needs.
### `--disable-proto=mode`
<!-- YAML
added:
- v13.12.0
- v12.17.0
-->
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`
<!-- YAML
added: v9.8.0
-->
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
`node:vm` module.
### `--expose-gc`
<!-- YAML
added: v22.3.0
-->
> Stability: 1 - Experimental. This flag is inherited from V8 and is subject to
> change upstream.
This flag will expose the gc extension from V8.
```js
if (globalThis.gc) {
globalThis.gc();
}
```
### `--dns-result-order=order`
<!-- YAML
added:
- v16.4.0
- v14.18.0
changes:
- version:
- v22.1.0
- v20.13.0
pr-url: https://github.com/nodejs/node/pull/52492
description: The `ipv6first` is supported now.
- version: v17.0.0
pr-url: https://github.com/nodejs/node/pull/39987
description: Changed default value to `verbatim`.
-->
Set the default value of `order` in [`dns.lookup()`][] and
[`dnsPromises.lookup()`][]. The value could be:
* `ipv4first`: sets default `order` to `ipv4first`.
* `ipv6first`: sets default `order` to `ipv6first`.
* `verbatim`: sets default `order` to `verbatim`.
The default is `verbatim` and [`dns.setDefaultResultOrder()`][] have higher
priority than `--dns-result-order`.
### `--enable-fips`
<!-- YAML
added: v6.0.0
-->
Enable FIPS-compliant crypto at startup. (Requires Node.js to be built
against FIPS-compatible OpenSSL.)
### `--enable-network-family-autoselection`
<!-- YAML
added: v18.18.0
-->
Enables the family autoselection algorithm unless connection options explicitly
disables it.
### `--enable-source-maps`
<!-- YAML
added: v12.12.0
changes:
- version:
- v15.11.0
- v14.18.0
pr-url: https://github.com/nodejs/node/pull/37362
description: This API is no longer experimental.
-->
Enable [Source Map v3][Source Map] support for stack traces.
When using a transpiler, such as TypeScript, stack traces thrown by an
application reference the transpiled code, not the original source position.
`--enable-source-maps` enables caching of Source Maps and makes a best
effort to report stack traces relative to the original source file.
Overriding `Error.prepareStackTrace` may prevent `--enable-source-maps` from
modifying the stack trace. Call and return the results of the original
`Error.prepareStackTrace` in the overriding function to modify the stack trace
with source maps.
```js
const originalPrepareStackTrace = Error.prepareStackTrace;
Error.prepareStackTrace = (error, trace) => {
// Modify error and trace and format stack trace with
// original Error.prepareStackTrace.
return originalPrepareStackTrace(error, trace);
};
```
Note, enabling source maps can introduce latency to your application
when `Error.stack` is accessed. If you access `Error.stack` frequently
in your application, take into account the performance implications
of `--enable-source-maps`.
### `--env-file=config`
> Stability: 1.1 - Active development
<!-- YAML
added: v20.6.0
changes:
- version:
- v21.7.0
- v20.12.0
pr-url: https://github.com/nodejs/node/pull/51289
description: Add support to multi-line values.
-->
Loads environment variables from a file relative to the current directory,
making them available to applications on `process.env`. The [environment
variables which configure Node.js][environment_variables], such as `NODE_OPTIONS`,
are parsed and applied. If the same variable is defined in the environment and
in the file, the value from the environment takes precedence.
You can pass multiple `--env-file` arguments. Subsequent files override
pre-existing variables defined in previous files.
```bash
node --env-file=.env --env-file=.development.env index.js
```
The format of the file should be one line per key-value pair of environment
variable name and value separated by `=`:
```text
PORT=3000
```
Any text after a `#` is treated as a comment:
```text
# This is a comment
PORT=3000 # This is also a comment
```
Values can start and end with the following quotes: `` ` ``, `"` or `'`.
They are omitted from the values.
```text
USERNAME="nodejs" # will result in `nodejs` as the value.
```
Multi-line values are supported:
```text
MULTI_LINE="THIS IS
A MULTILINE"
# will result in `THIS IS\nA MULTILINE` as the value.
```
Export keyword before a key is ignored:
```text
export USERNAME="nodejs" # will result in `nodejs` as the value.
```
### `-e`, `--eval "script"`
<!-- YAML
added: v0.5.2
changes:
- version: v5.11.0
pr-url: https://github.com/nodejs/node/pull/5348
description: Built-in libraries are now available as predefined variables.
-->
Evaluate the following argument as JavaScript. The modules which are
predefined in the REPL can also be used in `script`.
On Windows, using `cmd.exe` a single quote will not work correctly because it
only recognizes double `"` for quoting. In Powershell or Git bash, both `'`
and `"` are usable.
### `--experimental-default-type=type`
<!-- YAML
added:
- v21.0.0
- v20.10.0
- v18.19.0
-->
> Stability: 1.0 - Early development
Define which module system, `module` or `commonjs`, to use for the following:
* String input provided via `--eval` or STDIN, if `--input-type` is unspecified.
* Files ending in `.js` or with no extension, if there is no `package.json` file
present in the same folder or any parent folder.
* Files ending in `.js` or with no extension, if the nearest parent
`package.json` field lacks a `"type"` field; unless the `package.json` folder
or any parent folder is inside a `node_modules` folder.
In other words, `--experimental-default-type=module` flips all the places where
Node.js currently defaults to CommonJS to instead default to ECMAScript modules,
with the exception of folders and subfolders below `node_modules`, for backward
compatibility.
Under `--experimental-default-type=module` and `--experimental-wasm-modules`,
files with no extension will be treated as WebAssembly if they begin with the
WebAssembly magic number (`\0asm`); otherwise they will be treated as ES module
JavaScript.
### `--experimental-detect-module`
<!-- YAML
added:
- v21.1.0
- v20.10.0
-->
> Stability: 1.1 - Active development
Node.js will inspect the source code of ambiguous input to determine whether it
contains ES module syntax; if such syntax is detected, the input will be treated
as an ES module.
Ambiguous input is defined as:
* Files with a `.js` extension or no extension; and either no controlling
`package.json` file or one that lacks a `type` field; and
`--experimental-default-type` is not specified.
* String input (`--eval` or STDIN) when neither `--input-type` nor
`--experimental-default-type` are specified.
ES module syntax is defined as syntax that would throw when evaluated as
CommonJS. This includes the following:
* `import` statements (but _not_ `import()` expressions, which are valid in
CommonJS).
* `export` statements.
* `import.meta` references.
* `await` at the top level of a module.
* Lexical redeclarations of the CommonJS wrapper variables (`require`, `module`,
`exports`, `__dirname`, `__filename`).
### `--experimental-eventsource`
<!-- YAML
added: v22.3.0
-->
Enable exposition of [EventSource Web API][] on the global scope.
### `--experimental-import-meta-resolve`
<!-- YAML
added:
- v13.9.0
- v12.16.2
changes:
- version:
- v20.6.0
- v18.19.0
pr-url: https://github.com/nodejs/node/pull/49028
description: synchronous import.meta.resolve made available by default, with
the flag retained for enabling the experimental second argument
as previously supported.
-->
Enable experimental `import.meta.resolve()` parent URL support, which allows
passing a second `parentURL` argument for contextual resolution.
Previously gated the entire `import.meta.resolve` feature.
### `--experimental-loader=module`
<!-- YAML
added: v8.8.0
changes:
- version: v12.11.1
pr-url: https://github.com/nodejs/node/pull/29752
description: This flag was renamed from `--loader` to
`--experimental-loader`.
-->
> This flag is discouraged and may be removed in a future version of Node.js.
> Please use
> [`--import` with `register()`][module customization hooks: enabling] instead.
Specify the `module` containing exported [module customization hooks][].
`module` may be any string accepted as an [`import` specifier][].
### `--experimental-network-imports`
<!-- YAML
added:
- v17.6.0
- v16.15.0
-->
> Stability: 1 - Experimental
Enable experimental support for the `https:` protocol in `import` specifiers.
### `--experimental-permission`