browserslist

What is browserslist?

The browserslist npm package is used to share target browsers and Node.js versions between different front-end tools, like Autoprefixer, Babel, and others. It utilizes a configuration file or package.json entries to specify the range of browser versions that your project supports. It helps in making decisions for transpiling JavaScript, adding vendor prefixes to CSS, and even defining which browser versions to test during the development process.

What are browserslist's main functionalities?

Defining target browsers

This feature allows you to define a range of browsers your project supports by specifying queries like market share, last versions, or excluding certain browsers. The code sample would typically be placed in a package.json file.

"browserslist": ["> 1%", "last 2 versions", "not dead"]

Integration with build tools

Browserslist can be integrated with build tools like Webpack, Babel, or PostCSS to automatically apply browser-specific transformations based on the defined browser support criteria.

const browserslist = require('browserslist');
const supportedBrowsers = browserslist('> 0.5%, last 2 versions, Firefox ESR, not dead');

CLI Usage

Browserslist provides a command-line interface (CLI) that can be used to check which browsers and versions are selected by your queries.

npx browserslist "> 1%, last 2 versions"

Configuring environments

You can define different sets of browsers for various environments, like production or development, within a .browserslistrc file.

[production]
> 1% in US
[development]
last 1 chrome version

Other packages similar to browserslist

caniuse-api

The caniuse-api provides raw browser support data from Can I Use, which is similar to the data that browserslist uses. However, it focuses more on querying specific features for browser support rather than defining a list of supported browsers for a project.

autoprefixer

Autoprefixer is a CSS post-processor that uses browserslist to add vendor prefixes to CSS rules. It is a consumer of browserslist data rather than a direct alternative, but it serves a similar purpose in terms of browser compatibility.

@babel/preset-env

Babel's preset-env is a smart preset that allows you to use the latest JavaScript without needing to micromanage which syntax transforms are needed by your target environment. It uses browserslist to determine which features need to be transformed or polyfilled. While not a direct alternative, it shares the goal of adapting code to be compatible with different environments.

README

Browserslist

Get browser versions that match given criteria. Useful for tools like Autoprefixer.

You can select browsers by passing a string. This library will use Can I Use data to return list of all matching versions. For example, query to select all browser versions that are the last version of each major browser, or have a usage of over 10% in global usage statistics:

browserslist('last 1 version, > 10%');
//=> ["and_chr 51", "chrome 53", "chrome 52", "edge 14", "firefox 49",
//    "ie 11", "ie_mob 11", "ios_saf 10", "opera 39", "safari 10"]

To share browser support with users, you can use browserl.ist.

Queries

Browserslist will use browsers criterias from:

1. First argument.
2. BROWSERSLIST environment variable.
3. browserslist config file in current or parent directories.
4. If all methods will not give a result, Browserslist will use defaults: > 1%, last 2 versions, Firefox ESR.

Multiple criteria are combined as a boolean OR. A browser version must match at least one of the criteria to be selected.

You can specify the versions by queries (case insensitive):

• last 2 versions: the last 2 versions for each major browser.
• last 2 Chrome versions: the last 2 versions of Chrome browser.
• > 5%: versions selected by global usage statistics.
• > 5% in US: uses USA usage statistics. It accepts two-letter country code.
• > 5% in my stats: uses custom usage data.
• ie 6-8: selects an inclusive range of versions.
• Firefox > 20: versions of Firefox newer than 20.
• Firefox >= 20: versions of Firefox newer than or equal to 20.
• Firefox < 20: versions of Firefox less than 20.
• Firefox <= 20: versions of Firefox less than or equal to 20.
• Firefox ESR: the latest [Firefox ESR] version.
• iOS 7: the iOS browser version 7 directly.
• not ie <= 8: exclude browsers selected before by previous queries. You can add not to any query.

Browserslist works with separated versions of browsers. You should avoid queries like Firefox > 0.

All queries are based on the Can I Use support table, e. g. last 3 iOS versions might select 8.4, 9.2, 9.3 (mixed major & minor), whereas last 3 Chrome versions might select 50, 49, 48 (major only).

Browsers

Names are case insensitive:

Major Browsers

• Chrome for Google Chrome.
• Firefox or ff for Mozilla Firefox.
• Explorer or ie for Internet Explorer.
• Edge for Microsoft Edge.
• iOS or ios_saf for iOS Safari.
• Opera for Opera.
• Safari for desktop Safari.
• ExplorerMobile or ie_mob for Internet Explorer Mobile.

Other

• Android for Android WebView.
• BlackBerry or bb for Blackberry browser.
• ChromeAndroid or and_chr for Chrome for Android (in Other section, because mostly same as common Chrome).
• FirefoxAndroid or and_ff for Firefox for Android.
• OperaMobile or op_mob for Opera Mobile.
• OperaMini or op_mini for Opera Mini.
• Samsung for Samsung Internet.
• UCAndroid or and_uc for UC Browser for Android.

Config File

Browserslist’s config should be named browserslist and have browsers queries split by a new line. Comments starts with # symbol:

# Browsers that we support

> 1%
Last 2 versions
IE 8 # sorry

Browserslist will check config in every directory in path. So, if tool process app/styles/main.css, you can put config to root, app/ or app/styles.

You can specify direct path to config by config option or BROWSERSLIST_CONFIG environment variables.

Environment Variables

If some tool use Browserslist inside, you can change browsers settings by environment variables:

• BROWSERSLIST with browsers queries.

  BROWSERSLIST="> 5%" gulp css
  

• BROWSERSLIST_CONFIG with path to config file.

  BROWSERSLIST_CONFIG=./config/browserslist gulp css
  

• BROWSERSLIST_STATS with path to the custom usage data.

  BROWSERSLIST_STATS=./config/usage_data.json gulp css
  

Custom Usage Data

If you have a website, you can query against the usage statistics of your site:

1. Import your Google Analytics data into Can I Use. Press Import… button in Settings page.

2. Open browser DevTools on [caniuse.com] add paste this snippet into Console:

   var e=document.createElement('a');e.setAttribute('href', 'data:text/plain;charset=utf-8,'+encodeURIComponent(JSON.stringify(JSON.parse(localStorage['usage-data-by-id'])[localStorage['config-primary_usage']])));e.setAttribute('download','stats.json');document.body.appendChild(e);e.click();document.body.removeChild(e);
   

3. Save data to file in your project.

4. Give it to Browserslist by stats option or BROWSERSLIST_STATS environment variable:

   browserslist('> 5% in my stats', { stats: 'path/to/the/stats.json' });
   

Of course, you can generate usage statistics file by any other method. Option stats accepts path to file or data itself:

var custom = {
    ie: {
        6: 0.01,
        7: 0.4,
        8: 1.5
    },
    chrome: {
        …
    },
    …
};

browserslist('> 5% in my stats', { stats: custom });

Note that you can query against your custom usage data while also querying against global or regional data. For example, the query > 5% in my stats, > 1%, > 10% in US is permitted.

Usage

var browserslist = require('browserslist');

// Your CSS/JS build tool code
var process = function (css, opts) {
    var browsers = browserslist(opts.browsers, { path: opts.file });
    // Your code to add features for selected browsers
}

Queries can be a string "> 5%, last 1 version" or an array ['> 5%', 'last 1 version'].

If a query is missing, Browserslist will look for a config file. You can provide a path option (that can be a file) to find the config file relatively to it.

For non-JS environment and debug purpose you can use CLI tool:

browserslist "> 1%, last 2 version"

Coverage

You can get total users coverage for selected browsers by JS API:

browserslist.coverage(browserslist('> 1%')) //=> 81.4

browserslist.coverage(browserslist('> 1% in US'), 'US') //=> 83.1

Or by CLI:

$ browserslist --coverage "> 1%"
These browsers account for 81.4% of all users globally

$ browserslist --coverage=US "> 1% in US"
These browsers account for 83.1% of all users in the US