browserslist-useragent-regexp

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A utility to compile browserslist query to a RegExp to test browser useragent. Simplest example: you can detect supported browsers on client-side.

1) Create .browserslistrc config, for example like this:

``
last 2 versions
not dead
`

2) Add script to package.json:

`json
{
"scripts": {
"supportedBrowsers": "browserslist-useragent-regexp --allowHigherVersions -o supportedBrowsers.js"
}
}
`
or supportedBrowsers.ts for typescript.

3) Run this script, to compile RegExp:

`bash
npm run supportedBrowsers


or


yarn supportedBrowsers
`

supportedBrowsers.js:

`js
module.exports = /((CPU[ +]OS|iPhone[ +]OS|CPU[ +]iPhone|CPU IPhone OS)[ +]+(11_\.|12_\.)(?:[_\.]\d+)?)|(OperaMini(?:\/att)?\/?(\d+)?(?:\.\d+)?(?:\.\d+)?)|(Opera\/.+Opera Mobi.+Version\/46\.0)|(Opera\/46\.0.+Opera Mobi)|(Opera Mobi.+Opera(?:\/|\s+)46\.0)|(SamsungBrowser\/(8|9)\.2)|(Edge\/(17|18)(?:\.0)?)|(HeadlessChrome(?:\/(72|73)\.0\.\d+)?)|((Chromium|Chrome)\/(72|73)\.0(?:\.\d+)?)|(IEMobile[ \/]11\.0)|(Version\/12\.(0|1)(?:\.\d+)?.Safari\/)|(Trident\/7\.0)|(Firefox\/(65|66)\.0\.\d+)|(Firefox\/(65|66)\.0(pre|[ab]\d+[a-z])?)|(([MS]?IE) 11\.0)/;
`

4) Import RegExp from created file:

`js
const {SupportedBrowsers} = require('./supportedBrowsers');

if (SupportedBrowsers.test(navigator.userAgent)) {
alert('Your browser is supported.');
}
`

for ts

`ts
import {SupportedBrowsers} from './supportedBrowsers';
`

Install

`bash
npm i -D browserslist-useragent-regexp


or


yarn add -D browserslist-useragent-regexp
`

Why?

As was written in article "Smart Bundling: Shipping legacy code to only legacy browsers": you can determinate, which bundle you should give to browser from server with browserslist-useragent. But in this case you must have your own server with special logic. Now, with browserslist-useragent-regexp, you can move that to client-side.

Development was inspired by this proposal from Mathias Bynens.

How to make differential resource loading and other optimizations with browserslist-useragent-regexp you can read in article "Speed up with Browserslist".

Demo (sources, build script).

CLI

`bash
npx browserslist-useragent-regexp [query] [...options]


or


yarn exec -- browserslist-useragent-regexp [query] [...options]
`

| Option | Description | Default |
|--------|-------------|---------|
| query | Manually provide a browserslist query. Specifying this overrides the browserslist configuration specified in your project. | |
| ‑‑help, -h | Print this message. | |
| ‑‑verbose, -v | Print additional info about RegExps. | |
| ‑‑ignorePatch | Ignore differences in patch browser numbers. | true |
| ‑‑ignoreMinor | Ignore differences in minor browser versions. | false |
| ‑‑allowHigherVersions | For all the browsers in the browserslist query, return a match if the useragent version is equal to or higher than the one specified in browserslist. | false |
| ‑‑allowZeroSubversions | Ignore match of patch or patch and minor, if they are 0. | false |

JS API basics

Module exposes two main methods:

$3

Compile browserslist query to RegExps for each browser.

$3

Compile browserslist query to one RegExp.

> Description of all methods you can find in Documentation.

#### Options

| Option | Type | Default | Description |
|--------|------|---------|-------------|
| browsers | string \| string[] | — | Manually provide a browserslist query (or an array of queries). Specifying this overrides the browserslist configuration specified in your project. |
| env | string | — | When multiple browserslist environments are specified, pick the config belonging to this environment. |
| ignorePatch | boolean | true | Ignore differences in patch browser numbers. |
| ignoreMinor | boolean | false | Ignore differences in minor browser versions. |
| allowHigherVersions | boolean | false | For all the browsers in the browserslist query, return a match if the useragent version is equal to or higher than the one specified in browserslist. |
| allowZeroSubversions | boolean | false | Ignore match of patch or patch and minor, if they are 0. |

#### RegExp info object

| Property | Type | Description |
|----------|------|-------------|
| family | string | Browser family. |
| requestVersions | [number, number, number][] | Versions provided by browserslist. |
| regExp | RegExp | RegExp to match useragent with family and versions. |
| sourceRegExp | RegExp | Original useragent RegExp, without versions. |
| resultFixedVersion | [number, number, number] \| null | Useragent version of RegExp. |
| resultMinVersion | [number, number, number] \| null | Useragent min version of RegExp. |
| resultMaxVersion | [number, number, number] \| null` | Useragent max version of RegExp. |

Other

- Supported browsers
- Notes
- When querying for modern browsers