webext-detect

Detects where the current browser extension code is being run.

This package was recently renamed from webext-detect-page to webext-detect

Install

You can download the standalone bundle and include it in your manifest.json.

Or use npm:

npm install webext-detect

Usage

import {isBackground, isContentScript} from 'webext-detect';

if (isBackground()) {
    // Run background code, e.g.
    browser.runtime.onMessage.addListener(console.log);
} else if (isContentScript()) {
    // Run content script code, e.g.
    browser.runtime.sendMessage('wow!');
}

API

The functions are only ever evaluated once. This protects from future "invalidated context" errors. Read the note about testing if you're running this code in a tester.

To see all the available functions, check the index.d.ts file.

There are also a few helper functions based on the useragent string to loosely detect the current browser: isChrome(), isFirefox(), isSafari(), isMobileSafari(). They are not intended to detect forks, but just the main engines.

Testing

The calls are automatically cached so, if you're using this in a test environment, import and call this function first to ensure that the environment is "detected" every time:

import {disableWebextDetectPageCache} from 'webext-detect';
disableWebextDetectPageCache();

Related

• webext-options-sync - Helps you manage and autosave your extension's options.
• webext-storage-cache - Map-like promised cache storage with expiration.
• webext-patterns - Utilities for patterns and globs.
• More…

License

MIT © Federico Brigante