Registry / devops / source-map-loader

source-map-loader

library5.0.0jsnpmunverified

Webpack loader that extracts inline and linked source maps from JavaScript files, including from node_modules, so webpack can process them for the generated bundle. Current stable version is 5.0.0 (2024-01-15), with major releases roughly yearly. Key differentiator: it ensures source map continuity across third-party libraries, preventing misinterpretation by browsers. Requires webpack 5+ and Node.js 18.12+ as of v5. Supports a filterSourceMappingUrl option to control per-file behavior.

devops

npm install source-map-loader

github ↗package ↗

INSTALL

IMPORT

SIG · SOURCE-MAP-LOADER

source-map-loader

devopsjavascriptv5.0.0

Install

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Import

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Disk

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Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

source-map-loader (default)

✓ module.exports = { module: { rules: [{ test: /\.js$/, enforce: 'pre', use: ['source-map-loader'] }] } }

Used as a webpack loader in config, not imported in application code.

require('source-map-loader')

✓ const sourceMapLoader = require('source-map-loader'); // not typical

✗ import sourceMapLoader from 'source-map-loader'; // used in config, not runtime

Loader is referenced by name string in webpack config, not imported directly.

filterSourceMappingUrl option

✓ options: { filterSourceMappingUrl: (url, resourcePath) => { ... } }

Function option for per-file source map URL handling.

Configures source-map-loader to process all JavaScript files before other loaders, extracting source maps. Includes ignoring parse warnings typical for third-party libraries.

// webpack.config.js module.exports = { module: { rules: [ { test: /\.js$/, enforce: 'pre', use: ['source-map-loader'], }, ], }, ignoreWarnings: [/Failed to parse source map/], }; // Then run webpack > npx webpack --mode development

Debug

Known issues

breakingMinimum Node.js version bumped to 18.12.0 in v5.0.0

fix

Upgrade Node.js to >=18.12.0

affects: >=5.0.0

breakingMinimum Node.js version bumped to 14.15.0 in v4.0.0

fix

Upgrade Node.js to >=14.15.0

affects: >=4.0.0 <5.0.0

breakingMinimum webpack version bumped to 5 in v2.0.0

fix

Upgrade webpack to >=5

affects: >=2.0.0

gotchaSource maps from node_modules are processed by default; can slow builds

fix

Use exclude: /node_modules/ in rule to avoid processing third-party maps if not needed

affects: >=0

deprecatedThe `source-map-js` package replaced `source-map` in v2.0.1 for performance

fix

No action needed; it's internal

affects: >=2.0.1

Errors

Common errors & fixes

Failed to parse source map from '...' Error: ENOENT: no such file or directory, open '...'

Linked source map URL points to a file that does not exist

fix

Ensure the source map file exists or use filterSourceMappingUrl to skip/remove the URL

WARNING in ./node_modules/... Module Warning (from ./node_modules/source-map-loader/dist/cjs.js): Failed to parse source map from '...' Error: data:...

Inline source map is malformed or uses unsupported encoding

fix

Update the library providing the source map or ignore warnings via ignoreWarnings config

Error: Cannot find module 'source-map-js'

Missing internal dependency (should be included but might be missing if manually installed incorrectly)

fix

Reinstall source-map-loader: npm install source-map-loader --save-dev

Upgrade

Version history

5.0.0latest on npm

Audit

Dependencies

webpackrequiredpeer dependency required at runtime; loader only works within webpack

Agent activity

9 hits · last 30 days

node

Resources

githubhttps://github.com/webpack-contrib/source-map-loader ↗

packagehttps://www.npmjs.com/package/source-map-loader ↗