optimize-css-mq

Optimize CSS media queries by combining them together and injecting at end of base styles.

Install

# npm
$ npm install optimize-css-mq --dev

# yarn
$ yarn add optimize-css-mq -D

Example

Input

.foo {
  width: 240px;
}

@media screen and (min-width: 768px) {
  .foo {
    width: 576px;
  }
}

.bar {
  width: 160px;
}

@media screen and (min-width: 768px) {
  .bar {
    width: 384px;
  }
}

Output

.foo {
  width: 240px;
}

.bar {
  width: 160px;
}

@media screen and (min-width: 768px) {
  .foo {
    width: 576px;
  }
  .bar {
    width: 384px;
  }
}

Usage

PostCSS Plugin

#!/usr/bin/env node

const fs = require("fs");
const postcss = require("postcss");

postcss([
  ...
  require("optimize-css-mq")()
])
  .process(fs.readFileSync("from.css", "utf8"))
  .then(function (result) => result.css);

Node.js Module

#!/usr/bin/env node

const fs = require("fs");
const optmizemq = require("optimize-css-mq");

console.log(
  optmizemq.pack(fs.readFileSync("from.css", "utf8"), {
    from: "from.css",
    map: {
      inline: false,
    },
    to: "to.css",
  }).css
);

Webpack Plugin

import OptimizeCssMqPlugin from "optimize-css-mq/webpack";

new OptimizeCssMqPlugin({
  input: resolver("../path/to/file.css"),
  output: resolver("../path/to/file-optimized.css"),
});

CLI

This package also installs a command line interface.

$ node ./node_modules/.bin/optmizemq --help
Usage: optmizemq [options] INPUT [OUTPUT]

Description:
  Pack same CSS media query rules into one using PostCSS

Options:
  -s, --sort       Sort “min-width” queries.
      --sourcemap  Create source map file.
  -h, --help       Show this message.
      --version    Print version information.

Use a single dash for INPUT to read CSS from standard input.

Examples:
  $ optmizemq fragmented.css
  $ optmizemq fragmented.css > packed.css

--sort option does not currently support a custom function.

Options

sort

By default, CSS optmizemq pack and order media queries as they are defined ([the “first win” algorithm][1]). If you want to sort media queries automatically, pass sort: true to this module.

postcss([
  optmizemq({
    sort: true,
  }),
]).process(css);

Currently, this option only supports min-width queries with specific units (ch, em, ex, px, and rem). If you want to do more, you need to create your own sorting function and pass it to this module like this:

postcss([
  optmizemq({
    sort: function (a, b) {
      return a.localeCompare(b);
    },
  }),
]).process(css);

In this example, all your media queries will sort by A-Z order.

This sorting function is directly passed to Array#sort() method of an array of all your media queries.

API

.pack(css, [options])

Packs media queries in css.

The second argument is optional. The options are:

• [options][2] mentioned above
• the second argument of [PostCSS’s process() method][3]

You can specify both at the same time.

const fs = require("fs");
const optmizemq = require("optimize-css-mq");

const result = optmizemq.pack(fs.readFileSync("from.css", "utf8"), {
  from: "from.css",
  map: {
    inline: false,
  },
  sort: true,
  to: "to.css",
});
fs.writeFileSync("to.css", result.css);
fs.writeFileSync("to.css.map", result.map);

Licnse

MIT