4.2.0 (November 26, 2020)
- Trim Custom Property values when possible (#393)
- Fixed removing unit for zero-length dimentions in min(),max()andclamp()functions (#426)
- Fixed crash on bad value in TRBL declaration value (#412)
4.1.1 (November 15, 2020)
- Fixed build setup to exclude full mdn/datathat reduced the lib size:
- dist/csso.js: 794.5Kb -> 255.2Kb
- dist/csso.min.js: 394.4Kb -> 194.2Kb
- package size: 237.8 kB -> 156.1 kB
- package unpacked size: 1.3 MB -> 586.8 kB
 
4.1.0 (October 27, 2020)
- Bumped CSSTree to ^1.0.0
- Fixed wrongly merging of TRBL values when one of them contains var()(#420)
- Fixed wrongly merging of pseudo class and element with the same name, e.g. :-ms-input-placeholderand::-ms-input-placeholder(#383, #416)
- Fixed wrongly merging of overflowfallback (#415)
4.0.3 (March 24, 2020)
4.0.2 (October 28, 2019)
- Fixed clean stage to avoid exceptions when source has unparsed or bad parts (#380)
- Fixed wrong percentage sign removal for zero values (#395)
4.0.1 (October 22, 2019)
- Bumped CSSTree to 1.0.0-alpha.37to avoid source map generation inconsistency across Node.js versions
4.0.0 (October 21, 2019)
- Dropped support for Node.js < 8
- Refreshed dev dependencies and scripts
- Bumped CSSTree to 1.0.0-alpha.36(#399)
- Changed bundle files: dist/csso.jsanddist/csso.min.jsinstead singledist/csso-browser.js(min version)
- Expose compress()assyntax.compress()
3.5.1 (June 7, 2018)
- Bumped CSSTree to 1.0.0-alpha.29(fixes some issues)
3.5.0 (January 14, 2018)
3.4.0 (November 3, 2017)
- Added percent sign removal for zero percentages for some properties that is safe (@RubaXa, #286)
- Removed unit removal for zero values in -ms-flexdue it breaks flex in IE10/11 (#362)
- Improved performance of selectors comparison (@smelukov, #343)
3.3.1 (October 17, 2017)
- Fixed merge of positiondeclarations whenstickyfallback is using (@gruzzilkin, #356)
3.3.0 (October 12, 2017)
- Migrated to CSSTree 1.0.0-alpha25
- Changed AST format (see CSSTree change log for details)
- Fixed performance issue when generate CSS with source map (quadratic increase in time depending on the size of the CSS)
 
3.2.0 (September 10, 2017)
- Fixed named color compression to apply only when an identifier is guaranteed to be a color
- Added lifting of @keyframesto the beginning of style sheet (chunk), but after@charsetand@importrules
- Added removal of @keyframes,@mediaand@supportswith no prelude
- Added removal of duplicate @keyframes(#202)
- Added new option forceMediaMergeto force media rules merging. It's unsafe in general, but works fine in many cases. Use it on your own risk (#350)
- Bumped CSSTreeto1.0.0-alpha23
3.1.1 (April 25, 2017)
- Fixed crash on a number processing when it used not in a list (#335)
3.1.0 (April 24, 2017)
- Implemented optimisation for nonekeyword inborderandoutlineproperties (@zoobestik, #41)
- Implemented replacing rgba(x, x, x, 0)totransparent
- Fixed plus sign omitting for numbers following identifier, hex color, number or unicode range, since it can change the meaning of CSS (e.g. calc(1px+2px)has been optimized tocalc(1px2px)before, now it stays the same)
- Improved usage filtering for nested selectors (i.e. for :nth-*(),:has(),:matchesand other pseudos)
- Implemented blacklistfiltering in usage (#334, see Black list filtering)
- Improved white space removing, now white spaces are removing in the beginning and at the ending of sequences, and between stylesheet and block nodes
- Bumped CSSTreeto1.0.0-alpha19
3.0.1 (March 14, 2017)
- Fixed declaration merging when declaration contains an !important
3.0.0 (March 13, 2017)
- Migrated to CSSTree as AST backend and exposed its API behind syntaxproperty
- Extracted CLI into standalone package css/csso-cli
2.3.1 (January 6, 2017)
- Added \0IE hack support (#320)
2.3.0 (October 25, 2016)
- Added beforeCompressandafterCompressoptions support (#316)
- Fixed crash on empty argument in function (#317)
2.2.1 (July 25, 2016)
- Fixed shorthand optimisation issue when value has a color value or something unknown (#311)
- Fixed cursorbroken fallback (#306)
2.2.0 (June 23, 2016)
- Implement AST cloning by adding clone()function andcloneoption forcompress()function (#296)
- Fix parse and translate attribute selector with flags but w/o operator (i.e. [attrName i])
- Don't merge rules with flagged attribute selectors with others (#291)
- Take in account functions when merge TRBL-properties (#297, thanks to @ArturAralin)
- Improve partial merge (#304)
- Tweak scanner, reduce code deoptimizations and other small improvements
2.1.1 (May 11, 2016)
- Fix wrong declaration with \9hack merge (#295)
2.1.0 (May 8, 2016)
- New option commentsto specify what comments to left:exclamation,first-exclamationandnone
- Add offsetto CSS parse error details
- Fix token offsetcomputation
2.0.0 (April 5, 2016)
- No more gonzalesAST format and related code
- minify()and- minifyBlock()is always return an object as result now (i.e.- { css: String, map: SourceMapGenerator or null })
- parse()- 
- Returns AST in new format (so called internal)
- Dynamic scanner implemented
- New AST format + dynamic scanner = performance boost and less memory consumption
- No more contextargument, context should be specified viaoptions
- Supported contexts now: stylesheet,atrule,atruleExpression,ruleset,selector,simpleSelector,block,declarationandvalue
- Drop needPositionsoption,positionsoption should be used instead
- Drop needInfooption,infoobject is attaching to nodes when some information is requested byoptions
- optionsshould be an object, otherwise it treats as empty object
 
- compress()- 
- No more AST converting (performance boost and less memory consumption)
- Drop outputAstoption
- Returns an object as result instead of AST (i.e. { ast: Object })
 
- Drop methods: justDoIt(),stringify(),cleanInfo()
1.8.1 (March 30, 2016)
- Don't remove spaces after function/braces/urls since unsafe (#289)
1.8.0 (March 24, 2016)
- Usage data support:
- Filter rulesets by tag names, class names and ids white lists.
- More aggressive ruleset moving using class name scopes information.
- New CLI option --usageto pass usage data file.
 
- Improve initial ruleset merge
- Change order of ruleset processing, now it's left to right. Previously unmerged rulesets may prevent lookup and other rulesets merge.
- Difference in pseudo signature just prevents ruleset merging, but don't stop lookup.
- Simplify block comparison (performance).
 
- New method csso.minifyBlock()for css block compression (e.g.styleattribute content).
- Ruleset merge improvement: at-rules with block (like @mediaor@supports) now can be skipped during ruleset merge lookup if doesn't contain something prevents it.
- FIX: Add negation (:not()) to pseudo signature to avoid unsafe merge (old browsers doesn't support it).
- FIX: Check nested parts of value when compute compatibility. It fixes unsafe property merging.
1.7.1 (March 16, 2016)
- pass block mode to tokenizer for correct parsing of declarations properties with //hack
- fix wrongly @importand@charsetremoval on double exclamation comment
1.7.0 (March 10, 2016)
- support for CSS Custom Properties (#279)
- rework RTBL properties merge – better merge for values with special units and don't merge values with CSS-wide keywords (#255)
- remove redundant universal selectors (#178)
- take in account !importantwhen check for property overriding (#280)
- don't merge text-aligndeclarations with some values (#281)
- add spaces around /deep/combinator on translate, since it together with universal selector can produce a comment
- better keyword and property name resolving (tolerant to hacks and so on)
- integration improvements
- compression log function could be customized by loggeroption forcompress()andminify()
- make possible to set initial line and column for parser
 
1.6.4 (March 1, 2016)
1.6.3 (February 29, 2016)
- add fileto generated source map since other tools can relay on it in source map transform chain
1.6.2 (February 29, 2016)
- tweak some parse error messages and their positions
- fix :not()parsing and selector groups in:not()is supported now (#215)
- needPositionparser option is deprecated,- positionsoption should be used instead (- needPositionis used still if- positionsoption omitted)
- expose internal AST API as csso.internal.*
- minify()adds- sourcesContentby default when source map is generated
- bring back support for node.js 0.10until major release (#275)
1.6.1 (February 28, 2016)
- fix exception on zero length dimension compress outside declaration (#273)
1.6.0 (February 27, 2016)
- source maps support
- parser remake:
- various parsing issues fixed
- fix unicode sequence processing in ident (#191)
- support for flags in attribute selector (#270)
- position (line and column) of parse error (#109)
- 4x performance boost, less memory consumption
 
- compressor refactoring
- internal AST is using doubly linked lists (with safe transformation support during iteration) instead of arrays
- rename restructuringtorestructureoption forminify()/compress()(restructuringis alias forrestructurenow, with lower priority)
- unquote urls when possible (#141, #60)
 
- setup code coverage and a number of related fixes
- add eslint to check unused things
1.5.4 (January 27, 2016)
- one more fix (in restructRulesetthis time) with merge of rulesets when a ruleset with same specificity places between them (#264)
- disable partial merge of rulesets in @keyframesrulesets (until sure it's correct)
1.5.3 (January 25, 2016)
- don't override display values with different browser support (#259)
- fix publish issue (one of modules leak in development state)
1.5.2 (January 24, 2016)
- don't merge rulesets if between them a ruleset with same specificity (#264)
1.5.1 (January 14, 2016)
- ensure -is not used as an identifier in attribute selectors (thanks to @mathiasbynens)
- fix broken justDoIt()function
- various small fixes
1.5.0 (January 14, 2016)
Parser
Compressor
- split code base into small modules and related refactoring
- introduce internal AST format for compressor (gonzales→internalandinternal→gonzalesconvertors, walkers, translator)
- various optimizations: no snapshots, using caches and indexes
- sort selectors, merge selectors in alphabet order
- compute selector's specificity
- better ruleset restructuring, improve compression of partially equal blocks
- better ruleset merge – not only closest but also disjoined by other rulesets when safe
- join @mediawith same query
- outputAst– new option to specify output AST format (- gonzalesby default for backward compatibility)
- remove quotes surrounding attribute values in attribute selectors when possible (#73)
- replace from→0%and100%→toat@keyframes(#205)
- prevent partial merge of rulesets at @keyframes(#80, #197)
API
- walker for gonzalesAST was implemented
CLI
- new option --stat(output stat instderr)
- new optional parameter levelfor--debugoption
1.4.4 (December 10, 2015)
- prevent removal of spaces after braces that before identifier that breaking at-rules expressions (#258)
1.4.3 (December 4, 2015)
- fix unicode-range parsing that cause to wrong function detection (#250)
1.4.2 (November 9, 2015)
- allow spaces between progid:and rest part of value for IE'sfilterproperty asautoprefixergenerates this kind of code (#249)
- fixes for Windows:
- correct processing new lines
- normalize file content in test suite
 
- fixes to work in strict mode (#252)
- init compressor dictionaries for every css block (#248, #251)
- bump uglify-js version
1.4.1 (October 20, 2015)
- allow merge for displayproperty (#167, #244)
- more accurate rect(clipproperty value) merge
- fix typo when specifying options in cli (thanks to @Taritsyn)
- fix safe unit values merge with keyword values (#244)
- fix wrong descendant combinator removal (#246)
- build browser version on prepublish(thanks to @silentroach)
- parser: store whitespaces as single token (performance and reduce memory consumption)
- rearrange compress tests layout
1.4 (October 16, 2015)
Bringing project back to life. Changed files structure, cleaned up and refactored most of sources.
Common
- single code base (no more srcfolder)
- build browser version with browserify(no moremake, andwebfolder), browser version is available atdist/csso-browser.js
- main file is lib/index.jsnow
- minimal node.jsversion is0.12now
- restrict file list to publish on npm (no more useless folders and files in package)
- add jscsto control code style
- automate gh-pagesupdate
- util functions reworked
- translator reworked
- test suite reworked
- compressor refactored
- initial parser refactoring
API
- new method minify(src, options), options:
- restructuring– if set to- false, disable structure optimisations (- trueby default)
- debug- outputs intermediate state of CSS during compression (- falseby default)
 
- deprecate justDoIt()method (useminifyinstead)
- rename treeToString()method tostringify()
- drop printTree()method
- AST node info
- columnand- offsetadded
- lnrenamed to- line
- fix line counting across multiple files and input with CR LF (#147)
 
CLI
- completely reworked, use clap to parse argv
- add support for input from stdin (#128)
- drop undocumented and obsoleted options --ruleand--parser(suppose nobody use it)
- drop -offalias for--restructure-offas incorrect (only one letter options should starts with single-)
- new option --debugthat reflecting tooptions.debugforminify
Parsing and optimizations
- keep all exclamation comments (#194)
- add /deep/combinator support (#209)
- attribute selector
- allow colon in attribute name (#237)
- support for namespaces (#233)
 
- color
- support all css/html colors
- convert hslatorgbaandhlstorgb
- convert rgbawith 1 as alpha value torgb(#122)
- interpolate rgbandrgbapercentage values to absolute values
- replace percentage values in rgbafor normalized/interpolated values
- lowercase hex colors and color names (#169)
- fix color minification when hex value replaced for color name (#176)
- fit rgb values to 0..255 range (#181)
 
- calc
- remove spaces for multiple operator in calc
- don't remove units inside calc (#222)
- fix wrong white space removal around +and-(#228)
 
- don't remove units in flexproperty as it could change value meaning (#200)
- don't merge \9hack values (#231)
- merge property values only if they have the same functions (#150, #227)
- don't merge property values with some sort of units (#140, #161)
- fix !importantissue fortop-right-bottom-leftproperties (#189)
- fix top-right-bottom-leftproperties merge (#139, #175)
- support for unicode-range (#148)
- don't crash on ruleset with no selector (#135)
- tolerant to class names that starts with digit (#99, #105)
- fix background compressing (#170)
1.3.12 (October 8, 2015)
- Case insensitive check for !important(#187)
- Fix problems with using cssoas cli command on Windows (#83, #136, #142 and others)
- Remove byte order marker (the UTF-8 BOM) from input
- Don't strip space between funktion-funktion and funktion-vhash (#134)
- Don't merge TRBL values having \9 (hack for IE8 in bootstrap) (#159, #214, #230, #231 and others)
- Don't strip units off dimensions of non-length (#226, #229 and others)
1.3.7 (February 11, 2013)
1.3.6 (November 26, 2012)
1.3.5 (October 28, 2012)
1.3.4 (October 10, 2012)
1.3.3 (October 9, 2012)
1.3.2 (October 8, 2012)
1.3.1 (October 8, 2012)
1.3.0 (October 4, 2012)
- PeCode CSS parser replaced by Gonzales CSS parser