PostCSS is a software development tool that uses

JavaScript JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of websites use JavaScript on the client side for webpage behavior, of ...

-based plugins to automate routine CSS operations. It was designed by Andrey Sitnik with the idea taking its origin in his front-end work for Evil Martians.

Functionality

PostCSS is a framework to develop CSS tools. It can be used to develop a template language such as Sass and LESS. The PostCSS core consists of: * CSS

parser Parsing, syntax analysis, or syntactic analysis is the process of analyzing a string of symbols, either in natural language, computer languages or data structures, conforming to the rules of a formal grammar. The term ''parsing'' comes from Lat ...

that generates an

abstract syntax tree In computer science, an abstract syntax tree (AST), or just syntax tree, is a tree representation of the abstract syntactic structure of text (often source code) written in a formal language. Each node of the tree denotes a construct occurr ...

* Set of classes that comprises the tree * CSS generator that generates a CSS line for the object tree * Code map generator for the CSS changes made Features are made available through plugins. The plugins are small programs working with the object tree. After the core has transformed a CSS string into an object tree, the plugins analyze and change the tree. Then PostCSS generates a new CSS string for the plugin-changed tree. PostCSS and its plugins are written in

and distributed through npm, which offer APIs for low-level JavaScript operations. There are official tools making it possible to use PostCSS with build systems such as Webpack, Gulp, and Grunt. There is also a console interface available. Browserify or Webpack can be used to open PostCSS in a browser.

Syntaxes

PostCSS allows changing the

and generator. In this case, PostCSS could be used to work with the

Less Less or LESS may refer to: fewer than,: not as much. Computing * less (Unix), a Unix utility program * Less (stylesheet language), a dynamic stylesheet language * Large-Scale Scrum (LeSS), a product development framework that extends Scrum Othe ...

and SCSS sources. However, PostCSS on its own cannot compile Sass or Less to CSS. What it does is change the original files — for instance, by sorting the CSS properties or checking the code for mistakes. PostCSS supports SugarSS.

Plugins

PostCSS plugins perform different CSS processing tasks ranging from analysis and properties sorting to minification. The complete plugin list can be found on postcss.parts, with some examples listed below. * Autoprefixer to add and clear browser prefixes. * CSS Modules to get CSS selectors isolated and code organized. It is supplied as part of Webpack. * stylelint to analyze CSS code for mistakes and check style consistency. * stylefmt fixes the CSS code according to the stylelint settings. * PreCSS to perform some Sass/

preprocessing functions. * postcss-preset-env to emulate features from unfinished CSS specification drafts. * cssnano to make CSS smaller in size by getting rid of the spaces and rewriting the code. * RTLCSS to change CSS code so that the design should be suitable for

right-to-left In a script (commonly shortened to right to left or abbreviated RTL, RL-TB or R2L), writing starts from the right of the page and continues to the left, proceeding from top to bottom for new lines. Arabic, Hebrew, Persian, Pashto, Urdu, Kashmir ...

writing (such is applied in

Arabic Arabic (, ' ; , ' or ) is a Semitic language spoken primarily across the Arab world.Semitic languages: an international handbook / edited by Stefan Weninger; in collaboration with Geoffrey Khan, Michael P. Streck, Janet C. E.Watson; Walter ...

and

Hebrew Hebrew (; ; ) is a Northwest Semitic language of the Afroasiatic language family. Historically, it is one of the spoken languages of the Israelites and their longest-surviving descendants, the Jews and Samaritans. It was largely preserved ...

). * postcss-assets, postcss-inline-svg and postcss-sprites to work with graphics.

History

During the course of the Rework project, the idea of modular CSS processing was suggested by TJ Holowaychuk September 1, 2012. February 28, 2013, TJ expressed it in public. March 14, 2013, Andrey Sitnik's front-end work for Evil Martians resulted in Autoprefixer, a Rework-based plugin. Initially, the plugin name was rework-vendors. As Autoprefixer grew, Rework could no longer to meet its needs. September 7, 2013, Andrey Sitnik started to develop PostCSS based on the Rework ideas. In 3 months, the first PostCSS plugin, grunt-pixrem was released. December 22, 2013, Autoprefixer version 1.0 migrated to PostCSS. For PostCSS, the primary style focus is

alchemy Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim world, ...

. The project logo represents the

philosopher's stone The philosopher's stone or more properly philosophers' stone (Arabic: حجر الفلاسفة, , la, lapis philosophorum), is a mythic alchemical substance capable of turning base metals such as mercury into gold (, from the Greek , "gold", ...

. Major and minor PostCSS versions get their names after the

Ars Goetia ''The Lesser Key of Solomon'', also known as ''Lemegeton Clavicula Salomonis'' or simply ''Lemegeton'', is an anonymous grimoire on demonology. It was compiled in the mid-17th century, mostly from materials a couple of centuries older.''Lemegeto ...

demons. For instance, version 1.0.0 is called Marquis Decarabia. The term postprocessor has caused some confusion. The PostCSS team used the term to show that PostCSS was not a template language (preprocessor) but a CSS tool. However, some developers think the term postprocessor would better suit browser tools (for instance, -prefix-free).The Trouble With Preprocessing Based on Future Specs
/ref> The situation has become even more complicated after the release of PreCSS. Now, instead of postprocessor, the PostCSS team use the term processor.

References

External links

* {{Stylesheet languages Cascading Style Sheets Parsing Software using the MIT license Free compilers and interpreters Free software programmed in JavaScript