csso-loader

library0.3.1jsnpmunverified

Webpack loader for CSS minification using CSSO. Current stable version is 0.3.1, with basic support for CSSO's restructure, comments, debug, and usage options. This loader allows inline query parameters or a top-level 'csso' config object. It works with webpack 1.x (loaders array) and has limited updates since last release; modern webpack versions may require a different loader syntax. It integrates after css-loader to minify CSS output.

web-framework devops

npm install csso-loader

github ↗package ↗

INSTALL

IMPORT

SIG · CSSO-LOADER

csso-loader

web-frameworkjavascriptv0.3.1

Install

—

Import

—

Disk

—

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.

default

✓ module.exports = { module: { loaders: [ { test: /\.css$/, loader: 'css-loader!csso-loader' } ] } }

✗ import { csso-loader } from 'csso-loader'

The loader is used via webpack configuration, not imported directly in code. It must be chained after css-loader to minify CSS output.

csso

✓ new webpack.LoaderOptionsPlugin({ options: { csso: { restructure: false } } })

✗ import csso from 'csso-loader'

Options are passed via the 'csso' object in webpack config, not by importing the loader directly. Use LoaderOptionsPlugin for webpack 2+.

query parameters

✓ loader: 'css-loader!csso-loader?-restructure&comments=false'

✗ loader: 'csso-loader?restructure=false'

Query parameters use a minus sign to disable default options (e.g., -restructure). Boolean false requires the '?' prefix for disabled features.

Minimal webpack config using csso-loader after css-loader to minify CSS files.

// webpack.config.js module.exports = { entry: './index.js', output: { filename: 'bundle.js' }, module: { loaders: [ { test: /\.css$/, loader: 'css-loader!csso-loader', } ] } };

Debug

Known issues

deprecatedThis package uses webpack 1.x loader syntax. webpack 2+ uses rules.use or LoaderOptionsPlugin.

fix

For webpack 2+, replace 'loaders' with 'rules' and use 'loaderOptionsPlugin' to pass options or switch to style-loader / css-loader built-in minification.

affects: >=0.1.0

gotchaOptions in webpack config must be placed in top-level 'csso' object, not inside loader options.

fix

Either use query parameters in the loader string, or add 'csso' as a top-level key in webpack config.

affects: >=0.1.0

gotchaLoader chain order: css-loader must come before csso-loader (rightmost in loader string).

fix

Always use 'css-loader!csso-loader' in loader string so csso-loader receives already-parsed CSS.

affects: >=0.1.0

breakingCSSo 4.0+ dropped some options, but csso-loader pins to older csso version.

fix

Pin csso version to 3.x or migrate to a modern minifier like css-minimizer-webpack-plugin.

affects: >=0.3.0

Errors

Common errors & fixes

Module build failed: Error: No handler for content type 'text/css'

csso-loader receives non-CSS content, e.g., from css-loader output with modules enabled.

fix

Disable CSS modules for the rule targeted by csso-loader, or use a different minifier.

Invalid configuration object. Webpack has been initialised using a configuration object that does not match the API schema.

Using webpack 2+ and placing options in 'csso' object without LoaderOptionsPlugin.

fix

Wrap csso options in new webpack.LoaderOptionsPlugin({ options: { csso: { restructure: false } } }) and apply to the correct loaders.

Error: Cannot find module 'csso'

csso not installed or not in node_modules.

fix

Install csso as a devDependency: npm install csso --save-dev

Upgrade

Version history

0.3.1latest on npm

Audit

Dependencies

cssorequiredpeer dependency for CSSO minification

webpackrequiredruntime peer dependency for loader context

Agent activity

2 hits · last 30 days

node

Resources

githubhttps://github.com/sandark7/csso-loader ↗

packagehttps://www.npmjs.com/package/csso-loader ↗