Extending Regex

1. Write Your Own Extension

To extend UAParser.js with your own regular expressions, you can pass a list of regexes to the extensions parameter when creating a new UAParser instance. This allows you to detect additional user-agent patterns that are not provided by default.

• UAParser(uastring?: string, extensions?: UAParserExt, headers?: UAParserHeaders)

// Example:
const myOwnListOfBrowsers = [
    [/(mybrowser)\/([\w\.]+)/i], [UAParser.BROWSER.NAME, UAParser.BROWSER.VERSION, ['type', 'bot']]
];

const myUA = 'Mozilla/5.0 MyBrowser/1.3';

const myParser = new UAParser({ browser: myOwnListOfBrowsers });

console.log(myParser.setUA(myUA).getBrowser());  // {name: "MyBrowser", version: "1.3", major: "1", type : "bot"}
console.log(myParser.getBrowser().is('bot'));    // true

// Another example:
const myOwnListOfDevices = [
    [/(mytab) ([\w ]+)/i], [UAParser.DEVICE.VENDOR, UAParser.DEVICE.MODEL, [UAParser.DEVICE.TYPE, UAParser.DEVICE.TABLET]],
    [/(myphone)/i], [UAParser.DEVICE.VENDOR, [UAParser.DEVICE.TYPE, UAParser.DEVICE.MOBILE]]
];

const myUA2 = 'Mozilla/5.0 MyTab 14 Pro Max';

const myParser2 = new UAParser({
    browser: myOwnListOfBrowsers,
    device: myOwnListOfDevices
});

console.log(myParser2.setUA(myUA2).getDevice());  // {vendor: "MyTab", model: "14 Pro Max", type: "tablet"}

TIP

When you pass custom regexes into the UAParser constructor, they will be ordered before the internal regexes. When the parser runs, it will first check the user-agent string against your custom regexes before checking against the internal regexes. This allows you to prioritize your custom patterns over the default ones.

2. Use Predefined Extensions Submodule

To use the predefined extensions, you can import the desired extensions from the ua-parser-js/extensions🡭 submodule.

// Usage example
// Import the UAParser class and the extensions
import { UAParser } from 'ua-parser-js';
import { Emails } from 'ua-parser-js/extensions';

// Define a user-agent string
const ua = 'Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.13.0';

// Create a new parser instance with the Emails extension
const browser = new UAParser(Emails)
                    .setUA(ua)
                    .getBrowser();

// Output the parsed browser information
console.log(browser.toString()); // Thunderbird 78.13.0

You can also create a parser with multiple extensions:

import { UAParser } from 'ua-parser-js';
import { Emails, Crawlers, Fetchers } from 'ua-parser-js/extensions';

// Multiple extensions can be passed as an array
const extendedParser = new UAParser([Emails, Crawlers, Fetchers]);