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doiuse
======
Lint CSS for browser support against caniuse database.
# Install
```sh
npm install -g doiuse
```
# Developing
```sh
git clone git@github.com:anandthakker/doiuse.git
cd doiuse
npm install
npm run babel
```
That last step transpiles the ES6 from src/ to ES5 in lib/. Already happens as a `pretest` step for `npm test`.
# Usage Examples
## Command Line
```bash
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
```javascript
var postcss = require('postcss');
var doiuse = require('doiuse');
postcss(doiuse({
browsers:['ie >= 6', '> 1%'],
ignore: ['rem'], // an optional array of features to ignore
ignoreFiles: ['**/normalize.css'], // an optional array of file globs to match against original source file path, to ignore
onFeatureUsage: function(usageInfo) {
console.log(usageInfo.message);
}
})).process("a { background-size: cover; }")
```
## Gulp
```javascript
var gulp = require('gulp')
var postcss = require('postcss')
var doiuse = require('doiuse')
gulp.src(src, { cwd: process.cwd() })
.pipe(gulp.postcss([
doiuse({
browsers: [
'ie >= 8',
'> 1%'
],
ignore: ['rem'], // an optional array of features to ignore
ignoreFiles: ['**/normalize.css'], // an optional array of file globs to match against original source file path, to ignore
onFeatureUsage: function (usageInfo) {
console.log(usageInfo.message)
}
})
]))
```
# How it works
In particular, the approach to detecting features usage is currently quite naive.
Refer to the data in [/data/features.js](data/features.js).
- 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.
# API Details:
## As a transform stream
```javascript
var doiuse = require('doiuse/stream');
process.stdin
.pipe(doiuse({ browsers: ['ie >= 8', '> 1%'], ignore: ['rem'] }))
.on('data', function (usageInfo) {
console.log(JSON.stringify(usageInfo))
})
```
Yields `UsageInfo` objects as described below.
## As a postcss plugin
`postcss(doiuse(opts)).process(css)`, where `opts` is:
```javascript
{
browsers: ['ie >= 8', '> 1%'], // an autoprefixer-like array of browsers.
ignore: ['rem'], // an optional array of features to ignore
ignoreFiles: ['**/normalize.css'], // an optional array of file globs to match against original source file path, to ignore
onFeatureUsage: function(usageInfo) { } // a callback for usages of features not supported by the selected browsers
}
```
And `usageInfo` looks like this:
```javascript
{
message: ': line , col - 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.
## Ignoring file-specific rules:
For disabling some checks you can use just-in-place comments
##### `/* doiuse-disable */`
Disables checks of _all [features](#features-list)_
##### `/* doiuse-disable feature */`
Disables checks of _specified [feature(s)](#features-list)_ (can be comma separated list)
##### `/* doiuse-enable */`
Re-enables checks of _all [features](#features-list)_
##### `/* doiuse-enable feature */`
Enables checks of _specified [feature(s)](#features-list)_ (can be comma separated list)
- for following lines in file
# [Contributing](CONTRIBUTING.md)
doiuse is an [OPEN Open Source](http://openopensource.org/) Project. This means that:
Individuals making significant and valuable contributions are given commit-access to the project to contribute as they see fit. This project is more like an open wiki than a standard guarded open source project.
# License
MIT
**NOTE:** Many of the files in test/cases are from autoprefixer-core, Copyright 2013 Andrey Sitnik . Please see https://github.com/postcss/autoprefixer-core.