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Convert values with PostCSS (e.g. ms -> s)
Last release 2 days ago
02 Oct 2026
Release timing varies
gaps range from 8 days to 4 months
Most releases are documented
notes for 50 of the last 60 stable releases
Nothing withdrawn
no release was ever pulled
11 years old
97 releases · first in 2015
Write numbers in scientific notation when it is shorter, such as 1e-6px for 0.000001px and 1e6px for 1000000px. This also applies when length unit con
Write numbers in scientific notation when it is shorter, such as 1e-6px for 0.000001px and 1e6px for 1000000px. This also applies when length unit conversion is disabled. Numbers written without a decimal point, such as z-index:1000000, keep their form, because an <integer> cannot use scientific notation.
Require Browserslist 4.29.3 or later.
### Patch Changes - fix: update browserslist
One column per quarter.
fix(postcss-svgo): decode SVG following WHATWG specification in #1975
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@9.0.4...cssnano@9.0.5
unicode-range) in font descriptors and custom properties, preventing code point ranges from being corrupted into invalid numbers or dimensions.fix: update postcss-calc in #1970
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@9.0.3...cssnano@9.0.4
Preserves percentage units in registered custom-property initial values with composite syntax, ranges, groups, and multipliers, and avoids clamping numeric operands nested inside alpha-value functions.
Preserves zero percentage units in rgb(), rgba(), and modern CSS Color 4 functions to avoid invalid syntax, respects disabled time conversions for 0ms, clamps percentage opacity values adhering to CSS Color 4 alpha semantics, and improves compatibility with uppercase at-rules and vendor-prefixed keyframes.
Preserves zero length in columns shorthands and zero units inside @property with <angle-percentage> syntax, retaining keyframe percentage units under nested rules. Symmetrically rounds negative numbers when precision is configured, converts between metric units (mm, cm, q), preserves zero percentages on SVG stroke properties to retain transition interpolation, and caches Browserslist lookups across runs. Also preserves units inside CSS Fonts 5 override descriptors, anchor() functions, flex-basis, and IE-targeted sizing properties.
Value transforms now read the CSS Values 4 math function names from one mathFunctions table in cssnano-utils, so unit retention, box and shorthand merging, parameter and whitespace handling, and time classification agree on which functions count as math functions. Serialized output is unchanged.
perf: median 15% speed increase on test fixtures
update browserslist
Updated dependencies:
fix: update color parsing library in #1964
fix: update color parsing library in #1964
fix: update PostCSS and selector parser
fix: update conflict detection and color conversion CSS spec conformance
fix: update PostCSS peer dependency
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@9.0.2...cssnano@9.0.3
fix: add main and types to package manifests in #1958
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@9.0.1...cssnano@9.0.2
fix: update postcss and selector parser
fix: update PostCSS peer dependency
refactor: some small performance gains in #1955
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@9.0.0...cssnano@9.0.1
Migrate to ESM and simplify config loading in #1948
Probably backward-compatible for most users. Some changes to configuration loading documented in migration guide.
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@8.0.10...cssnano@9.0.0
^22.22.3 || ^24.15.0 || >=26.0. Package subpath imports are no longer supported. See the migration documentation before upgrading.Fix postcs-svgo encoding in #1877
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@8.0.3...cssnano@8.0.4
postcss-reduce-initial: update initial properties
packages now define an exports field in package.json. This prevents any file added to the package to automatically be exposed as a possible import. The has been done in a backward compatible way, so you should be able to import every file you did in the previous release.
types have also been regenerated with TypeScript 7.
Full Changelog: https://github.com/cssnano/cssnano/compare/cssnano@8.0.2...cssnano@8.0.3
chore: regenerate all type definitions with TypeScript 7
chore: regenerate all type definitions with TypeScript 7
fix: update svgo, autoprefixer and postcss
feat: make some packages runnable on the web without extra polyfills
fix: update PostCSS
chore: define package.json exports
chore: update dependencies
Update autoprefixer, browserslist, colordx and postcss
chore: update the postcss peer dependency
ea8e33a: chore: drop Node.js 20 support
ea8e33a: chore: drop Node.js 20 support
Node.js 20 has reached end of life.
### Patch Changes - 7e56dba: fix: update postcss
322ad33: fix: update postcss peer dependency
5cb8b09: fix: udpate browserslist
c3e537a: fix: update postcss-selector-parser
72dd9c9: fix: update browserslist
fix: do not strip % sign inside linear()
906a785: fix: update browserslist
5672148: fix: update PostCSS peer dependency to version without vulnerabilities
34bdcb8: fix(postcss-convert-values): convert 0ms to 0s
dff5c42: chore: update browserslist and postcss-selector-parser
d6f9a32: fix(postcss-convert-values): preserve percent sign in border-image-width
0c85fa9: fix: update Browserslist version
0d10597: chore: drop support for Node.js 14 and 16
feat: add preset and plugin options for browserslist
83d3268: chore: update autoprefixer and browerslist
3757056: fix: handle cases where AtRules might not have any children nodes
26bbbd3: chore: update minimum browserslist version to 4.22.2
18331a6: fix: update cssnano peer dependency to 8.4.31 to avoid security issue
ca9d3f55: Switch minimum supported Node version to 14 for all packages
fix: update autoprefixer and browserslist
chore: update TypeScript and improve types
postcss-convert-values: preserve percentage sign on IE 11
feature: add TypeScript type declarations
Publish untranspiled CommonJS source
refactor: remove implicit boolean conversion
All notable changes to this project will be documented in this file. See Conventional Commits for commit guidelines.
Nothing published for this version
Note: Version bump only for package postcss-convert-values
Note: Version bump only for package postcss-convert-values
Note: Version bump only for package postcss-convert-values
Note: Version bump only for package postcss-convert-values
Note: Version bump only for package postcss-convert-values
postcss version is 8.2.1Nothing published for this version
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browserslist version incompatibility with caniuse-api
browserslist version incompatibility with caniuse-apiWe dropped support for Node 4, now requiring at least Node 6.9.
border-spacing property.U to lowercase for IE <= 11 and Edge <= 15.a { border-style:dotted; border-style:var(--variable) }) correctly.border property with invalid border width value correctly.:-ms-input-placeholder and ::-ms-input-placeholder selectors correctly.all property correctly.url function.data and *-extension:// URLs correctly.all for IE.Includes the new release candidate for postcss-selector-parser 3.
@media \0screen\,screen\9 {} hacks
(thanks to @evilebottnawi).resolveConfig for a Root node without a source property
(thanks to @darthmaim).Since version 4 has been in-development for some time, we thought it would be best to release an alpha version so that we could catch any issues befor
Since version 4 has been in-development for some time, we thought it would be best to release an alpha version so that we could catch any issues before the actual release.
cssnano & its plugins have been upgraded to PostCSS 6.x. Please ensure that for optimal results that you use cssnano with a PostCSS 6 compatible runner & that any other plugins are also using PostCSS 6.
cssnano is now essentially a preset loader and does not contain any built-in
transforms (instead, it delegates to cssnano-preset-default by default).
Due to the new architecture, it's not possible to exclude asynchronous
transforms and run it synchronously, unlike in 3.x. Any transforms that
were "core" modules have now been extracted out into separate packages.
Because of the new preset system, cssnano will not accept any transformation options; these must be set in the preset. The option names remain mostly the same, except some cases where "core" modules have been extracted out:
core is now normalizeWhitespace.reduceBackgroundRepeat is now normalizeRepeatStyle.reduceDisplayValues is now normalizeDisplayValues.reducePositions is now normalizePositions.reduceTimingFunctions is now normalizeTimingFunctions.styleCache is now rawCache.When excluding transforms, we now have an exclude option (in 3.x this was
named disable). Similarly, the safe option was removed; the defaults
are now much less aggressive.
By default, the following transforms are no longer applied to any input CSS. You may see an increased output file size as a result:
autoprefixerpostcss-discard-unusedpostcss-merge-identspostcss-reduce-identspostcss-zindexNote that you can load cssnano-preset-advanced instead which does contain
these transforms.
We no longer detect previous plugins to silently exclude our own, and now
consider this to be an anti-pattern. So postcss-filter-plugins was removed.
We also changed some options to make the default transforms safer:
postcss-minify-font-values: removeAfterKeyword set to false from true.postcss-normalize-url: stripWWW set to false from true.cssnano now does not accept the sourcemap shortcut option; please refer
to the PostCSS documentation on sourcemaps. The quickstart.js file included
with this module will give you a good starting point.
cssnano.process is no longer a custom method; we use the built-in process
method exposed on each PostCSS plugin. The new signature is
cssnano.process(css, postcssOpts, cssnanoOpts), in 3.x it was
cssnano.process(css, cssnanoOpts).
We dropped support for Node 0.12, now requiring at least Node 4.
Finally, cssnano is now developed as a monorepo, due to the fact that some
transforms have a lot of grey area/overlap. Due to this, some modules have
been refactored to delegate responsibility to others, such that duplication
of functionality is minimized. For instance, postcss-colormin will no
longer compress whitespace or compress numbers, as those are handled by
postcss-normalize-whitespace & postcss-convert-values respectively.
clone behaviour. In cases where some utility
has been used by several plugins it is now a separate package, reducing
cssnano's footprint.postcss-colormin &
postcss-reduce-initial were enhanced with different behaviour depending
on which browsers are passed. And now, the footprint for the caniuse-db
dependency is much smaller thanks to caniuse-lite - 7 times smaller as
of this writing. This makes cssnano much faster to download from npm!Nothing published for this version
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