Implementation:Microsoft Playwright CrServiceWorker

Knowledge Sources	Microsoft_Playwright
Domains	Chromium, ServiceWorker
Last Updated	2026-02-12 00:00 GMT

Overview

Concrete tool for managing Chromium service worker targets with JavaScript execution, network interception, and console message support provided by the Playwright library.

Description

The `CRServiceWorker` class extends `Worker` and represents a Chromium service worker target. It creates a `CRExecutionContext` when the Runtime execution context is established, optionally sets up a `CRNetworkManager` for network inspection (unless disabled via `PLAYWRIGHT_DISABLE_SERVICE_WORKER_NETWORK`), and forwards console API calls as `ConsoleMessage` events on the browser context. The class handles service worker script loading detection (with version-gated behavior for Chromium 143+), network interception setup (request interception, extra HTTP headers, credentials, offline mode), and exception reporting.

Usage

Use CrServiceWorker when Playwright needs to interact with service workers in Chromium, including evaluating JavaScript, intercepting network requests, and capturing console output.

Code Reference

Source Location

• Repository: Microsoft_Playwright
• File: packages/playwright-core/src/server/chromium/crServiceWorker.ts

Signature

export class CRServiceWorker extends Worker {
  readonly browserContext: CRBrowserContext;
  constructor(browserContext: CRBrowserContext, session: CRSession, url: string);
}

Import

import { CRServiceWorker } from '../server/chromium/crServiceWorker';

I/O Contract

Inputs

Name	Type	Required	Description
browserContext	CRBrowserContext	Yes	The browser context owning this service worker
session	CRSession	Yes	CDP session for the service worker target
url	string	Yes	The URL of the service worker script

Outputs

Name	Type	Description
(events)	ConsoleMessage	Console messages emitted on the browser context
executionContext	CRExecutionContext	JavaScript execution context for evaluation

Usage Examples

import { CRServiceWorker } from '../server/chromium/crServiceWorker';

const worker = new CRServiceWorker(browserContext, crSession, 'https://example.com/sw.js');
// Worker automatically sets up execution context and network interception
// Console messages from the service worker are emitted on browserContext

Related Pages

• Environment:Microsoft_Playwright_Node_Runtime_Environment