cssnano

library7.1.7jsnpmunverified

A modular CSS minifier built on top of PostCSS, version 7.1.7. It optimizes CSS by removing whitespace, comments, duplicated rules, and applying transformations like merging rules, converting values, and minifying selectors. Release cadence is frequent with monthly patch releases. Key differentiators: modular design with presets (default, advanced, etc.), extensive plugin ecosystem, and deep PostCSS integration. Supports Node.js >=18.12.0, ships TypeScript declarations, and requires postcss@^8.5.10 as a peer dependency.

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INSTALL

IMPORT

SIG · CSSNANO

cssnano

http-networkingjavascriptv7.1.7

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Install & Compatibility

Where this runs

No compatibility data collected yet for this library.

Code

Verified usage

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

cssnano

✓ import cssnano from 'cssnano';

✗ const { default: cssnano } = require('cssnano');

Default export since version 7; used as a PostCSS plugin. For CJS, use require('cssnano').default.

defaultPreset

✓ import { defaultPreset } from 'cssnano';

✗ import defaultPreset from 'cssnano/presets/default';

Named export for the default preset since v7.

advancedPreset

✓ import { advancedPreset } from 'cssnano';

✗ const advancedPreset = require('cssnano/presets/advanced');

Named export for the advanced preset; also available as a named export from the main entry.

Demonstrates using cssnano as a PostCSS plugin to minify CSS with the default preset.

import postcss from 'postcss'; import cssnano from 'cssnano'; const input = 'h1 { color: red; color: red; }'; postcss([cssnano({ preset: 'default' })]) .process(input, { from: undefined }) .then(result => { console.log(result.css); // outputs: 'h1{color:red}' });

Debug

Known issues

breakingv7 changed the import path for presets; previously available as cssnano/presets/default, now exported as named exports from main entry.

fix

Use import { defaultPreset } from 'cssnano' instead of require('cssnano/presets/default').

affects: >=7.0.0

deprecatedThe 'safe' preset is deprecated and will be removed in a future version, use 'default' or 'advanced' with explicit options.

fix

Replace preset: 'safe' with preset: 'default' and adjust options if needed.

affects: >=5.0.0

gotchacssnano requires a from option in postcss.process when using a preset that relies on source maps; otherwise can fail silently.

fix

Always provide from: 'input.css' (or undefined) in the postcss options.

affects: >=4.0.0

breakingNode.js engine requirement increased to ^18.12.0 || ^20.9.0 || >=22.0 in v7, dropping support for Node 14 and 16.

fix

Upgrade Node.js to a supported version (18, 20, 22+).

affects: >=7.0.0

deprecatedThe 'postcss-discard-unused' and 'postcss-merge-idents' plugins are deprecated and will be removed; their functionality may be merged into core.

fix

Avoid relying on these plugins; use the main cssnano package without them.

affects: >=6.0.0

gotchaWhen using cssnano in a build tool like webpack with css-loader, ensure cssnano is applied after all other PostCSS plugins to maximize optimization.

fix

Place cssnano last in the PostCSS plugins array.

affects: >=5.0.0

Errors

Common errors & fixes

Error: PostCSS plugin cssnano requires PostCSS 8.0.0 or higher.

Mismatched postcss version; cssnano v7 requires postcss@^8.5.10.

fix

Run 'npm install postcss@^8.5.10' to upgrade postcss.

TypeError: cssnano is not a function

CommonJS require() returns an object with default property; need to call .default.

fix

Use const cssnano = require('cssnano').default; or switch to ESM import.

Error: Cannot find module 'cssnano/presets/default'

Import path changed in v7; presets now export from main entry.

fix

Use import { defaultPreset } from 'cssnano'; instead.

Warning: unknown preset 'safe'

The 'safe' preset was removed in recent versions.

fix

Use preset: 'default' instead.

Upgrade

Version history

7.1.7latest on npm

Audit

Dependencies

postcssrequiredpeer dependency; cssnano is a PostCSS plugin

Agent activity

17 hits · last 30 days

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Resources

githubhttps://github.com/cssnano/cssnano ↗

packagehttps://www.npmjs.com/package/cssnano ↗

homepagehttps://cssnano.github.io/cssnano ↗