Node.js v22.7.0 documentation
- Node.js v22.7.0
- Table of contents
-
Index
- Assertion testing
- Asynchronous context tracking
- Async hooks
- Buffer
- C++ addons
- C/C++ addons with Node-API
- C++ embedder API
- Child processes
- Cluster
- Command-line options
- Console
- Corepack
- Crypto
- Debugger
- Deprecated APIs
- Diagnostics Channel
- DNS
- Domain
- Errors
- Events
- File system
- Globals
- HTTP
- HTTP/2
- HTTPS
- Inspector
- Internationalization
- Modules: CommonJS modules
- Modules: ECMAScript modules
- Modules:
node:module
API - Modules: Packages
- Modules: TypeScript
- Net
- OS
- Path
- Performance hooks
- Permissions
- Process
- Punycode
- Query strings
- Readline
- REPL
- Report
- Single executable applications
- SQLite
- Stream
- String decoder
- Test runner
- Timers
- TLS/SSL
- Trace events
- TTY
- UDP/datagram
- URL
- Utilities
- V8
- VM
- WASI
- Web Crypto API
- Web Streams API
- Worker threads
- Zlib
- Other versions
- Options
Modules: node:module
API#
The Module
object#
Provides general utility methods when interacting with instances of
Module
, the module
variable often seen in CommonJS modules. Accessed
via import 'node:module'
or require('node:module')
.
module.builtinModules
#
A list of the names of all modules provided by Node.js. Can be used to verify if a module is maintained by a third party or not.
Note: the list doesn't contain prefix-only modules like node:test
.
module
in this context isn't the same object that's provided
by the module wrapper. To access it, require the Module
module:
// module.mjs
// In an ECMAScript module
import { builtinModules as builtin } from 'node:module';
// module.cjs
// In a CommonJS module
const builtin = require('node:module').builtinModules;
module.createRequire(filename)
#
filename
<string> | <URL> Filename to be used to construct the require function. Must be a file URL object, file URL string, or absolute path string.- Returns: <require> Require function
import { createRequire } from 'node:module';
const require = createRequire(import.meta.url);
// sibling-module.js is a CommonJS module.
const siblingModule = require('./sibling-module');
module.isBuiltin(moduleName)
#
moduleName
<string> name of the module- Returns: <boolean> returns true if the module is builtin else returns false
import { isBuiltin } from 'node:module';
isBuiltin('node:fs'); // true
isBuiltin('fs'); // true
isBuiltin('wss'); // false
module.register(specifier[, parentURL][, options])
#
specifier
<string> | <URL> Customization hooks to be registered; this should be the same string that would be passed toimport()
, except that if it is relative, it is resolved relative toparentURL
.parentURL
<string> | <URL> If you want to resolvespecifier
relative to a base URL, such asimport.meta.url
, you can pass that URL here. Default:'data:'
options
<Object>parentURL
<string> | <URL> If you want to resolvespecifier
relative to a base URL, such asimport.meta.url
, you can pass that URL here. This property is ignored if theparentURL
is supplied as the second argument. Default:'data:'
data
<any> Any arbitrary, cloneable JavaScript value to pass into theinitialize
hook.transferList
<Object[]> transferrable objects to be passed into theinitialize
hook.
Register a module that exports hooks that customize Node.js module resolution and loading behavior. See Customization hooks.
module.syncBuiltinESMExports()
#
The module.syncBuiltinESMExports()
method updates all the live bindings for
builtin ES Modules to match the properties of the CommonJS exports. It
does not add or remove exported names from the ES Modules.
const fs = require('node:fs');
const assert = require('node:assert');
const { syncBuiltinESMExports } = require('node:module');
fs.readFile = newAPI;
delete fs.readFileSync;
function newAPI() {
// ...
}
fs.newAPI = newAPI;
syncBuiltinESMExports();
import('node:fs').then((esmFS) => {
// It syncs the existing readFile property with the new value
assert.strictEqual(esmFS.readFile, newAPI);
// readFileSync has been deleted from the required fs
assert.strictEqual('readFileSync' in fs, false);
// syncBuiltinESMExports() does not remove readFileSync from esmFS
assert.strictEqual('readFileSync' in esmFS, true);
// syncBuiltinESMExports() does not add names
assert.strictEqual(esmFS.newAPI, undefined);
});
Customization Hooks#
Enabling#
Module resolution and loading can be customized by registering a file which
exports a set of hooks. This can be done using the register
method
from node:module
, which you can run before your application code by
using the --import
flag:
node --import ./register-hooks.js ./my-app.js
// register-hooks.js
import { register } from 'node:module';
register('./hooks.mjs', import.meta.url);
// register-hooks.js
const { register } = require('node:module');
const { pathToFileURL } = require('node:url');
register('./hooks.mjs', pathToFileURL(__filename));
The file passed to --import
can also be an export from a dependency:
node --import some-package/register ./my-app.js
Where some-package
has an "exports"
field defining the /register
export to map to a file that calls register()
, like the following register-hooks.js
example.
Using --import
ensures that the hooks are registered before any application
files are imported, including the entry point of the application. Alternatively,
register
can be called from the entry point, but dynamic import()
must be
used for any code that should be run after the hooks are registered:
import { register } from 'node:module';
register('http-to-https', import.meta.url);
// Because this is a dynamic `import()`, the `http-to-https` hooks will run
// to handle `./my-app.js` and any other files it imports or requires.
await import('./my-app.js');
const { register } = require('node:module');
const { pathToFileURL } = require('node:url');
register('http-to-https', pathToFileURL(__filename));
// Because this is a dynamic `import()`, the `http-to-https` hooks will run
// to handle `./my-app.js` and any other files it imports or requires.
import('./my-app.js');
In this example, we are registering the http-to-https
hooks, but they will
only be available for subsequently imported modules—in this case, my-app.js
and anything it references via import
(and optionally require
). If the
import('./my-app.js')
had instead been a static import './my-app.js'
, the
app would have already been loaded before the http-to-https
hooks were
registered. This due to the ES modules specification, where static imports are
evaluated from the leaves of the tree first, then back to the trunk. There can
be static imports within my-app.js
, which will not be evaluated until
my-app.js
is dynamically imported.
my-app.js
can also be CommonJS. Customization hooks will run for any
modules that it references via import
(and optionally require
).
Finally, if all you want to do is register hooks before your app runs and you
don't want to create a separate file for that purpose, you can pass a data:
URL to --import
:
node --import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register("http-to-https", pathToFileURL("./"));' ./my-app.js
Chaining#
It's possible to call register
more than once:
// entrypoint.mjs
import { register } from 'node:module';
register('./foo.mjs', import.meta.url);
register('./bar.mjs', import.meta.url);
await import('./my-app.mjs');
// entrypoint.cjs
const { register } = require('node:module');
const { pathToFileURL } = require('node:url');
const parentURL = pathToFileURL(__filename);
register('./foo.mjs', parentURL);
register('./bar.mjs', parentURL);
import('./my-app.mjs');
In this example, the registered hooks will form chains. These chains run
last-in, first out (LIFO). If both foo.mjs
and bar.mjs
define a resolve
hook, they will be called like so (note the right-to-left):
node's default ← ./foo.mjs
← ./bar.mjs
(starting with ./bar.mjs
, then ./foo.mjs
, then the Node.js default).
The same applies to all the other hooks.
The registered hooks also affect register
itself. In this example,
bar.mjs
will be resolved and loaded via the hooks registered by foo.mjs
(because foo
's hooks will have already been added to the chain). This allows
for things like writing hooks in non-JavaScript languages, so long as
earlier registered hooks transpile into JavaScript.
The register
method cannot be called from within the module that defines the
hooks.
Communication with module customization hooks#
Module customization hooks run on a dedicated thread, separate from the main thread that runs application code. This means mutating global variables won't affect the other thread(s), and message channels must be used to communicate between the threads.
The register
method can be used to pass data to an initialize
hook. The
data passed to the hook may include transferrable objects like ports.
import { register } from 'node:module';
import { MessageChannel } from 'node:worker_threads';
// This example demonstrates how a message channel can be used to
// communicate with the hooks, by sending `port2` to the hooks.
const { port1, port2 } = new MessageChannel();
port1.on('message', (msg) => {
console.log(msg);
});
port1.unref();
register('./my-hooks.mjs', {
parentURL: import.meta.url,
data: { number: 1, port: port2 },
transferList: [port2],
});
const { register } = require('node:module');
const { pathToFileURL } = require('node:url');
const { MessageChannel } = require('node:worker_threads');
// This example showcases how a message channel can be used to
// communicate with the hooks, by sending `port2` to the hooks.
const { port1, port2 } = new MessageChannel();
port1.on('message', (msg) => {
console.log(msg);
});
port1.unref();
register('./my-hooks.mjs', {
parentURL: pathToFileURL(__filename),
data: { number: 1, port: port2 },
transferList: [port2],
});
Hooks#
The register
method can be used to register a module that exports a set of
hooks. The hooks are functions that are called by Node.js to customize the
module resolution and loading process. The exported functions must have specific
names and signatures, and they must be exported as named exports.
export async function initialize({ number, port }) {
// Receives data from `register`.
}
export async function resolve(specifier, context, nextResolve) {
// Take an `import` or `require` specifier and resolve it to a URL.
}
export async function load(url, context, nextLoad) {
// Take a resolved URL and return the source code to be evaluated.
}
Hooks are part of a chain, even if that chain consists of only one
custom (user-provided) hook and the default hook, which is always present. Hook
functions nest: each one must always return a plain object, and chaining happens
as a result of each function calling next<hookName>()
, which is a reference to
the subsequent loader's hook (in LIFO order).
A hook that returns a value lacking a required property triggers an exception. A
hook that returns without calling next<hookName>()
and without returning
shortCircuit: true
also triggers an exception. These errors are to help
prevent unintentional breaks in the chain. Return shortCircuit: true
from a
hook to signal that the chain is intentionally ending at your hook.
Hooks are run in a separate thread, isolated from the main thread where
application code runs. That means it is a different realm. The hooks thread
may be terminated by the main thread at any time, so do not depend on
asynchronous operations (like console.log
) to complete.
initialize()
#
data
<any> The data fromregister(loader, import.meta.url, { data })
.
The initialize
hook provides a way to define a custom function that runs in
the hooks thread when the hooks module is initialized. Initialization happens
when the hooks module is registered via register
.
This hook can receive data from a register
invocation, including
ports and other transferrable objects. The return value of initialize
can be a
<Promise>, in which case it will be awaited before the main application thread
execution resumes.
Module customization code:
// path-to-my-hooks.js
export async function initialize({ number, port }) {
port.postMessage(`increment: ${number + 1}`);
}
Caller code:
import assert from 'node:assert';
import { register } from 'node:module';
import { MessageChannel } from 'node:worker_threads';
// This example showcases how a message channel can be used to communicate
// between the main (application) thread and the hooks running on the hooks
// thread, by sending `port2` to the `initialize` hook.
const { port1, port2 } = new MessageChannel();
port1.on('message', (msg) => {
assert.strictEqual(msg, 'increment: 2');
});
port1.unref();
register('./path-to-my-hooks.js', {
parentURL: import.meta.url,
data: { number: 1, port: port2 },
transferList: [port2],
});
const assert = require('node:assert');
const { register } = require('node:module');
const { pathToFileURL } = require('node:url');
const { MessageChannel } = require('node:worker_threads');
// This example showcases how a message channel can be used to communicate
// between the main (application) thread and the hooks running on the hooks
// thread, by sending `port2` to the `initialize` hook.
const { port1, port2 } = new MessageChannel();
port1.on('message', (msg) => {
assert.strictEqual(msg, 'increment: 2');
});
port1.unref();
register('./path-to-my-hooks.js', {
parentURL: pathToFileURL(__filename),
data: { number: 1, port: port2 },
transferList: [port2],
});
resolve(specifier, context, nextResolve)
#
specifier
<string>context
<Object>conditions
<string[]> Export conditions of the relevantpackage.json
importAttributes
<Object> An object whose key-value pairs represent the attributes for the module to importparentURL
<string> | <undefined> The module importing this one, or undefined if this is the Node.js entry point
nextResolve
<Function> The subsequentresolve
hook in the chain, or the Node.js defaultresolve
hook after the last user-suppliedresolve
hook- Returns: <Object> | <Promise>
format
<string> | <null> | <undefined> A hint to the load hook (it might be ignored)'builtin' | 'commonjs' | 'json' | 'module' | 'wasm'
importAttributes
<Object> | <undefined> The import attributes to use when caching the module (optional; if excluded the input will be used)shortCircuit
<undefined> | <boolean> A signal that this hook intends to terminate the chain ofresolve
hooks. Default:false
url
<string> The absolute URL to which this input resolves
Warning Despite support for returning promises and async functions, calls to
resolve
may block the main thread which can impact performance.
The resolve
hook chain is responsible for telling Node.js where to find and
how to cache a given import
statement or expression, or require
call. It can
optionally return a format (such as 'module'
) as a hint to the load
hook. If
a format is specified, the load
hook is ultimately responsible for providing
the final format
value (and it is free to ignore the hint provided by
resolve
); if resolve
provides a format
, a custom load
hook is required
even if only to pass the value to the Node.js default load
hook.
Import type attributes are part of the cache key for saving loaded modules into
the internal module cache. The resolve
hook is responsible for returning an
importAttributes
object if the module should be cached with different
attributes than were present in the source code.
The conditions
property in context
is an array of conditions for
package exports conditions that apply to this resolution
request. They can be used for looking up conditional mappings elsewhere or to
modify the list when calling the default resolution logic.
The current package exports conditions are always in
the context.conditions
array passed into the hook. To guarantee default
Node.js module specifier resolution behavior when calling defaultResolve
, the
context.conditions
array passed to it must include all elements of the
context.conditions
array originally passed into the resolve
hook.
export async function resolve(specifier, context, nextResolve) {
const { parentURL = null } = context;
if (Math.random() > 0.5) { // Some condition.
// For some or all specifiers, do some custom logic for resolving.
// Always return an object of the form {url: <string>}.
return {
shortCircuit: true,
url: parentURL ?
new URL(specifier, parentURL).href :
new URL(specifier).href,
};
}
if (Math.random() < 0.5) { // Another condition.
// When calling `defaultResolve`, the arguments can be modified. In this
// case it's adding another value for matching conditional exports.
return nextResolve(specifier, {
...context,
conditions: [...context.conditions, 'another-condition'],
});
}
// Defer to the next hook in the chain, which would be the
// Node.js default resolve if this is the last user-specified loader.
return nextResolve(specifier);
}
load(url, context, nextLoad)
#
url
<string> The URL returned by theresolve
chaincontext
<Object>conditions
<string[]> Export conditions of the relevantpackage.json
format
<string> | <null> | <undefined> The format optionally supplied by theresolve
hook chainimportAttributes
<Object>
nextLoad
<Function> The subsequentload
hook in the chain, or the Node.js defaultload
hook after the last user-suppliedload
hook- Returns: <Object>
format
<string>shortCircuit
<undefined> | <boolean> A signal that this hook intends to terminate the chain ofload
hooks. Default:false
source
<string> | <ArrayBuffer> | <TypedArray> The source for Node.js to evaluate
The load
hook provides a way to define a custom method of determining how a
URL should be interpreted, retrieved, and parsed. It is also in charge of
validating the import attributes.
The final value of format
must be one of the following:
format | Description | Acceptable types for source returned by load |
---|---|---|
'builtin' | Load a Node.js builtin module | Not applicable |
'commonjs' | Load a Node.js CommonJS module | { string , ArrayBuffer , TypedArray , null , undefined } |
'json' | Load a JSON file | { string , ArrayBuffer , TypedArray } |
'module' | Load an ES module | { string , ArrayBuffer , TypedArray } |
'wasm' | Load a WebAssembly module | { ArrayBuffer , TypedArray } |
The value of source
is ignored for type 'builtin'
because currently it is
not possible to replace the value of a Node.js builtin (core) module.
Omitting vs providing a source
for 'commonjs'
has very different effects:
- When a
source
is provided, allrequire
calls from this module will be processed by the ESM loader with registeredresolve
andload
hooks; allrequire.resolve
calls from this module will be processed by the ESM loader with registeredresolve
hooks; only a subset of the CommonJS API will be available (e.g. norequire.extensions
, norequire.cache
, norequire.resolve.paths
) and monkey-patching on the CommonJS module loader will not apply. - If
source
is undefined ornull
, it will be handled by the CommonJS module loader andrequire
/require.resolve
calls will not go through the registered hooks. This behavior for nullishsource
is temporary — in the future, nullishsource
will not be supported.
When node
is run with --experimental-default-type=commonjs
, the Node.js
internal load
implementation, which is the value of next
for the
last hook in the load
chain, returns null
for source
when format
is
'commonjs'
for backward compatibility. Here is an example hook that would
opt-in to using the non-default behavior:
import { readFile } from 'node:fs/promises';
export async function load(url, context, nextLoad) {
const result = await nextLoad(url, context);
if (result.format === 'commonjs') {
result.source ??= await readFile(new URL(result.responseURL ?? url));
}
return result;
}
Warning: The ESM
load
hook and namespaced exports from CommonJS modules are incompatible. Attempting to use them together will result in an empty object from the import. This may be addressed in the future.
These types all correspond to classes defined in ECMAScript.
- The specific
ArrayBuffer
object is aSharedArrayBuffer
. - The specific
TypedArray
object is aUint8Array
.
If the source value of a text-based format (i.e., 'json'
, 'module'
)
is not a string, it is converted to a string using util.TextDecoder
.
The load
hook provides a way to define a custom method for retrieving the
source code of a resolved URL. This would allow a loader to potentially avoid
reading files from disk. It could also be used to map an unrecognized format to
a supported one, for example yaml
to module
.
export async function load(url, context, nextLoad) {
const { format } = context;
if (Math.random() > 0.5) { // Some condition
/*
For some or all URLs, do some custom logic for retrieving the source.
Always return an object of the form {
format: <string>,
source: <string|buffer>,
}.
*/
return {
format,
shortCircuit: true,
source: '...',
};
}
// Defer to the next hook in the chain.
return nextLoad(url);
}
In a more advanced scenario, this can also be used to transform an unsupported source to a supported one (see Examples below).
Examples#
The various module customization hooks can be used together to accomplish wide-ranging customizations of the Node.js code loading and evaluation behaviors.
Import from HTTPS#
In current Node.js, specifiers starting with https://
are experimental (see
[HTTPS and HTTP imports][]).
The hook below registers hooks to enable rudimentary support for such specifiers. While this may seem like a significant improvement to Node.js core functionality, there are substantial downsides to actually using these hooks: performance is much slower than loading files from disk, there is no caching, and there is no security.
// https-hooks.mjs
import { get } from 'node:https';
export function load(url, context, nextLoad) {
// For JavaScript to be loaded over the network, we need to fetch and
// return it.
if (url.startsWith('https://')) {
return new Promise((resolve, reject) => {
get(url, (res) => {
let data = '';
res.setEncoding('utf8');
res.on('data', (chunk) => data += chunk);
res.on('end', () => resolve({
// This example assumes all network-provided JavaScript is ES module
// code.
format: 'module',
shortCircuit: true,
source: data,
}));
}).on('error', (err) => reject(err));
});
}
// Let Node.js handle all other URLs.
return nextLoad(url);
}
// main.mjs
import { VERSION } from 'https://coffeescript.org/browser-compiler-modern/coffeescript.js';
console.log(VERSION);
With the preceding hooks module, running
node --import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register(pathToFileURL("./https-hooks.mjs"));' ./main.mjs
prints the current version of CoffeeScript per the module at the URL in
main.mjs
.
Transpilation#
Sources that are in formats Node.js doesn't understand can be converted into
JavaScript using the load
hook.
This is less performant than transpiling source files before running Node.js; transpiler hooks should only be used for development and testing purposes.
// coffeescript-hooks.mjs
import { readFile } from 'node:fs/promises';
import { dirname, extname, resolve as resolvePath } from 'node:path';
import { cwd } from 'node:process';
import { fileURLToPath, pathToFileURL } from 'node:url';
import coffeescript from 'coffeescript';
const extensionsRegex = /\.(coffee|litcoffee|coffee\.md)$/;
export async function load(url, context, nextLoad) {
if (extensionsRegex.test(url)) {
// CoffeeScript files can be either CommonJS or ES modules, so we want any
// CoffeeScript file to be treated by Node.js the same as a .js file at the
// same location. To determine how Node.js would interpret an arbitrary .js
// file, search up the file system for the nearest parent package.json file
// and read its "type" field.
const format = await getPackageType(url);
const { source: rawSource } = await nextLoad(url, { ...context, format });
// This hook converts CoffeeScript source code into JavaScript source code
// for all imported CoffeeScript files.
const transformedSource = coffeescript.compile(rawSource.toString(), url);
return {
format,
shortCircuit: true,
source: transformedSource,
};
}
// Let Node.js handle all other URLs.
return nextLoad(url);
}
async function getPackageType(url) {
// `url` is only a file path during the first iteration when passed the
// resolved url from the load() hook
// an actual file path from load() will contain a file extension as it's
// required by the spec
// this simple truthy check for whether `url` contains a file extension will
// work for most projects but does not cover some edge-cases (such as
// extensionless files or a url ending in a trailing space)
const isFilePath = !!extname(url);
// If it is a file path, get the directory it's in
const dir = isFilePath ?
dirname(fileURLToPath(url)) :
url;
// Compose a file path to a package.json in the same directory,
// which may or may not exist
const packagePath = resolvePath(dir, 'package.json');
// Try to read the possibly nonexistent package.json
const type = await readFile(packagePath, { encoding: 'utf8' })
.then((filestring) => JSON.parse(filestring).type)
.catch((err) => {
if (err?.code !== 'ENOENT') console.error(err);
});
// If package.json existed and contained a `type` field with a value, voilà
if (type) return type;
// Otherwise, (if not at the root) continue checking the next directory up
// If at the root, stop and return false
return dir.length > 1 && getPackageType(resolvePath(dir, '..'));
}
# main.coffee
import { scream } from './scream.coffee'
console.log scream 'hello, world'
import { version } from 'node:process'
console.log "Brought to you by Node.js version #{version}"
# scream.coffee
export scream = (str) -> str.toUpperCase()
With the preceding hooks module, running
node --import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register(pathToFileURL("./coffeescript-hooks.mjs"));' ./main.coffee
causes main.coffee
to be turned into JavaScript after its source code is
loaded from disk but before Node.js executes it; and so on for any .coffee
,
.litcoffee
or .coffee.md
files referenced via import
statements of any
loaded file.
Import maps#
The previous two examples defined load
hooks. This is an example of a
resolve
hook. This hooks module reads an import-map.json
file that defines
which specifiers to override to other URLs (this is a very simplistic
implementation of a small subset of the "import maps" specification).
// import-map-hooks.js
import fs from 'node:fs/promises';
const { imports } = JSON.parse(await fs.readFile('import-map.json'));
export async function resolve(specifier, context, nextResolve) {
if (Object.hasOwn(imports, specifier)) {
return nextResolve(imports[specifier], context);
}
return nextResolve(specifier, context);
}
With these files:
// main.js
import 'a-module';
// import-map.json
{
"imports": {
"a-module": "./some-module.js"
}
}
// some-module.js
console.log('some module!');
Running node --import 'data:text/javascript,import { register } from "node:module"; import { pathToFileURL } from "node:url"; register(pathToFileURL("./import-map-hooks.js"));' main.js
should print some module!
.
Source map v3 support#
Helpers for interacting with the source map cache. This cache is populated when source map parsing is enabled and source map include directives are found in a modules' footer.
To enable source map parsing, Node.js must be run with the flag
--enable-source-maps
, or with code coverage enabled by setting
NODE_V8_COVERAGE=dir
.
// module.mjs
// In an ECMAScript module
import { findSourceMap, SourceMap } from 'node:module';
// module.cjs
// In a CommonJS module
const { findSourceMap, SourceMap } = require('node:module');
module.findSourceMap(path)
#
path
<string>- Returns: <module.SourceMap> | <undefined> Returns
module.SourceMap
if a source map is found,undefined
otherwise.
path
is the resolved path for the file for which a corresponding source map
should be fetched.
Class: module.SourceMap
#
new SourceMap(payload[, { lineLengths }])
#
payload
<Object>lineLengths
<number[]>
Creates a new sourceMap
instance.
payload
is an object with keys matching the Source map v3 format:
file
: <string>version
: <number>sources
: <string[]>sourcesContent
: <string[]>names
: <string[]>mappings
: <string>sourceRoot
: <string>
lineLengths
is an optional array of the length of each line in the
generated code.
sourceMap.payload
#
- Returns: <Object>
Getter for the payload used to construct the SourceMap
instance.
sourceMap.findEntry(lineOffset, columnOffset)
#
lineOffset
<number> The zero-indexed line number offset in the generated sourcecolumnOffset
<number> The zero-indexed column number offset in the generated source- Returns: <Object>
Given a line offset and column offset in the generated source file, returns an object representing the SourceMap range in the original file if found, or an empty object if not.
The object returned contains the following keys:
- generatedLine: <number> The line offset of the start of the range in the generated source
- generatedColumn: <number> The column offset of start of the range in the generated source
- originalSource: <string> The file name of the original source, as reported in the SourceMap
- originalLine: <number> The line offset of the start of the range in the original source
- originalColumn: <number> The column offset of start of the range in the original source
- name: <string>
The returned value represents the raw range as it appears in the SourceMap, based on zero-indexed offsets, not 1-indexed line and column numbers as they appear in Error messages and CallSite objects.
To get the corresponding 1-indexed line and column numbers from a
lineNumber and columnNumber as they are reported by Error stacks
and CallSite objects, use sourceMap.findOrigin(lineNumber, columnNumber)
sourceMap.findOrigin(lineNumber, columnNumber)
#
lineNumber
<number> The 1-indexed line number of the call site in the generated sourcecolumnNumber
<number> The 1-indexed column number of the call site in the generated source- Returns: <Object>
Given a 1-indexed lineNumber
and columnNumber
from a call site in
the generated source, find the corresponding call site location
in the original source.
If the lineNumber
and columnNumber
provided are not found in any
source map, then an empty object is returned. Otherwise, the
returned object contains the following keys:
- name: <string> | <undefined> The name of the range in the source map, if one was provided
- fileName: <string> The file name of the original source, as reported in the SourceMap
- lineNumber: <number> The 1-indexed lineNumber of the corresponding call site in the original source
- columnNumber: <number> The 1-indexed columnNumber of the corresponding call site in the original source