doiuse

What is doiuse?

The doiuse npm package is a tool for checking your CSS against browser support. It helps developers ensure that their CSS is compatible with the browsers they intend to support by identifying unsupported or partially supported CSS features.

What are doiuse's main functionalities?

Check CSS for browser support

This feature allows you to check your CSS code against a list of browsers to see if any features are not supported. The code sample demonstrates how to use doiuse with PostCSS to process a CSS string and log any warnings about unsupported features.

const doiuse = require('doiuse');
const postcss = require('postcss');

const css = 'a { display: flex; }';

postcss([doiuse({ browsers: ['> 1%', 'last 2 versions'] })])
  .process(css)
  .then(result => {
    result.warnings().forEach(warn => {
      console.warn(warn.toString());
    });
  });

Custom browser support configuration

This feature allows you to specify custom browser support configurations. The code sample shows how to configure doiuse to check CSS against Internet Explorer 10 and the last two versions of all other browsers.

const doiuse = require('doiuse');
const postcss = require('postcss');

const css = 'a { display: grid; }';

postcss([doiuse({ browsers: ['ie >= 10', 'last 2 versions'] })])
  .process(css)
  .then(result => {
    result.warnings().forEach(warn => {
      console.warn(warn.toString());
    });
  });

Other packages similar to doiuse

caniuse-lite

caniuse-lite is a smaller, more compact version of the caniuse database that provides data on browser support for various web technologies. Unlike doiuse, caniuse-lite does not directly check your CSS but provides the data that can be used by other tools to perform such checks.

autoprefixer

Autoprefixer is a PostCSS plugin that parses your CSS and adds vendor prefixes to CSS rules using values from the Can I Use database. While doiuse checks for unsupported features, Autoprefixer automatically adds necessary prefixes to ensure compatibility with specified browsers.

stylelint

Stylelint is a powerful CSS linter that helps you avoid errors and enforce consistent conventions in your stylesheets. It can be extended with plugins to check for browser compatibility issues, similar to doiuse, but offers a broader range of linting capabilities.

README

doiuse

Lint CSS for browser support against caniuse database.

NOTE: This is a very, very initial release. Feedback or contributions are quite welcome!

TL;DR

Command Line

doiuse --browsers "ie >= 9, > 1%, last 2 versions" main.css
# or
cat main.css | doiuse --browsers "ie >= 9, > 1%, last 2 versions"

Sample output:

/projects/website/main.css:5:3: CSS3 Box-sizing not supported by: IE (8,9,10,11), Chrome (36,37,38), Safari (8,7.1), Opera (24,25), iOS Safari (8,7.1,8.1), Android Browser (4.1,4.4,4.4.4), IE Mobile (10,11)
/projects/website/main.css:6:3: CSS3 Box-sizing not supported by: IE (8,9,10,11), Chrome (36,37,38), Safari (8,7.1), Opera (24,25), iOS Safari (8,7.1,8.1), Android Browser (4.1,4.4,4.4.4), IE Mobile (10,11)
/projects/website/main.css:8:3: CSS user-select: none not supported by: IE (8,9)
/projects/website/main.css:9:3: CSS user-select: none not supported by: IE (8,9)
/projects/website/main.css:10:3: CSS user-select: none not supported by: IE (8,9)
/projects/website/main.css:11:3: CSS user-select: none not supported by: IE (8,9)
/projects/website/main.css:12:3: CSS user-select: none not supported by: IE (8,9)
/projects/website/main.css:13:3: Pointer events not supported by: IE (8,9,10), Firefox (32,33), Chrome (36,37,38), Safari (8,7.1), Opera (24,25), iOS Safari (8,7.1,8.1), Android Browser (4.1,4.4,4.4.4), IE Mobile (10)
/projects/website/main.css:14:3: Pointer events not supported by: IE (8,9,10), Firefox (32,33), Chrome (36,37,38), Safari (8,7.1), Opera (24,25), iOS Safari (8,7.1,8.1), Android Browser (4.1,4.4,4.4.4), IE Mobile (10)
/projects/website/main.css:32:3: CSS3 Transforms not supported by: IE (8)

Use --json to get output as (newline-delimited) JSON objects.

JS

var postcss = require('postcss');
var doiuse = require('doiuse');

postcss(doiuse({
  browsers:['ie >= 6', '> 1%'],
  onUnsupportedFeatureUse: function(usageInfo) {
    console.log(usageInfo.message);
  }
})).process("a { background-size: cover; }")

How it works

In particular, the approach to detecting features usage is currently quite naive.

Refer to the data in /src/data/features.coffee.

• If a feature in that dataset only specifies properties, we just use those properties for regex/substring matches against the properties used in the input CSS.
• If a feature also specifies values, then we also require that the associated value matches one of those values.

TODO:

• Support @-rules
• Allow each feature to have multiple instances of the match criteria laid out above, so that different, disjoint (property, value) combinations can be used to detect a feature.
• Subfeatures, in to allow a slightly looser coupling with caniuse-db's structure (for handling, e.g., partial support, the different flexbox versions, etc.)
• Prefix-aware testing: i.e., pass along a list of prefixes used with a given feature. (This is low priority: just use autoprefixer.)

API Details:

As a transform stream

var doiuse = require('doiuse/stream');

process.stdin
  .pipe(doiuse(['ie >= 8', '> 1%']))
  .pipe(process.stdout);

Yields usage info in objects as described below.

As a postcss plugin

postcss(doiuse(opts)).process(css), where opts is:

{
  browserSelection: ['ie >= 8', '> 1%'] // an autoprefixer-like array of browsers.
  onUnsupportedFeatureUse: function(usageInfo) { } // a callback for usages of features not supported by the selected browsers
}

And usageInfo looks like this:

{
  message: '<input source>: line <l>, col <c> - CSS3 Gradients not supported by: IE (8)'
  feature: 'css-gradients', //slug identifying a caniuse-db feature
  featureData:{
    title: 'CSS Gradients',
    missing: "IE (8)" // string of browsers missing support for this feature.
    missingData: {
      // map of browser -> version -> (lack of)support code
      ie: { '8': 'n' }
    },
    caniuseData: { // data from caniuse-db/features-json/[feature].json }
  },
  usage: {} //the postcss node where that feature is being used.
}

Called once for each usage of each css feature not supported by the selected
browsers.

License

MIT

NOTE: Many of the files in test/cases are from autoprefixer-core, Copyright 2013 Andrey Sitnik [e-mail]. Please see https://github.com/postcss/autoprefixer-core.