Provecss NPM | npm.io

provecss

Write future-proved CSS from now.

provecss let us able to use @import, @media queries, variables in mobile-first webapp development without worring the performance. provecss could preprocess the origin css file and generate backward compatible css styles.

Features

Support test cases demostrate the input and output result of provecss.

Import inlining

Thanks to rework-importer

Input files:

imprt.css

@import url("imprt_core.css");
@import url("imprt_large.css");
@import url("imprt_xlarge.css");

imprt_core.css

headers {
  background-color: orange;
}

imprt_large.css

@media (min-width: 768px) {
  headers {
    background-color: black;
  }
}

imprt_xlarge.css

@media (min-width: 1024px) {
  headers {
    background-color: red;
  }
}

Output:

headers {
  background-color: orange;
}

@media (min-width: 768px) {
  headers {
    background-color: black;
  }
}

@media (min-width: 1024px) {
  headers {
    background-color: red;
  }
}

Import filtering

Pass import_filter option as 'core', 'large' to filter out other styles.

Output:

headers {
  background-color: orange;
}

@media (min-width: 768px) {
  headers {
    background-color: black;
  }
}

Media Query matching

An alternative way is to pass media_match option as filter creteria.

Input with { width: '1024px', height: '768px' } to match proper size of @media.

Output:

headers {
  background-color: orange;
}

@media (min-width: 1024px) {
  headers {
    background-color: red;
  }
}

Media Query extracting

Pass extra media_extract option as true

Output:

headers {
  background-color: orange;
}

headers {
  background-color: red;
}

In result, the was-@media section just overwrited the origin style.

CSS Variables replacing

Thanks to rework-vars

Pass vars option as true to opt-in variabls replacing.

Input:

:root {
  --main-color: orange;
}

body {
  color: var(--main-color);
}

Output:

body {
  color: orange;
}

Usage (in node)

You can install provecss via npm.

npm install provecss --save-dev

provecss input/output are strings. So you could chain it in any preprocessing position.

var provecss = require('provecss');
var fs = require('fs');

// read file
var input = fs.readFileSync('imprt.css', 'utf8');
var output = provecss(input);

// write file
fs.writeFileSync('imprt.out.css', output);

To inline @import files, you could pass path option and provecss will search and inline import files in path's directory:

provecss(input, {path: 'test/features/imprt.css'});

Options

browsers: Pass autoprefixer options here. pass firefox 24 or chrome 10 will generate browser only prefixes. provecss won't generate prefixes by default.
path: File path that contain @import.
base: Normally provecss will parsed the same directory as in file path. you could explicitly pass a path option for will-be-import styles.
media_filter: While precoess @import, The postfix _<target> will be filtered.
media_match: specify the match creteria to filter out @media conditions.
media_extract: set to true to remove @media statement.
vars: replace css variable while true. provecss won't do variable replacing by default.

Usage (with grunt)

Grunt plugin is available in https://www.npmjs.org/package/grunt-provecss Pass same options as use in node.

Usage (in command line)

You can Run command in console

provecss source target [options]

For example

provecss color.css color.out.css [options]

Options

--vars: enable css variable replacing
--import: enable import inlining
--filter [targets]: enable import filtering
--match [width]x[height]: enable media matching
--extract: enable media extracting
--browsers <browsers>, 'enable auto-prefixing, pass autoprefixer options here. all option is the short cut to fit all major browsers.