@exactjs/devtools-agent

Read-only programmatic access to eXact DevTools data through Chrome DevTools Protocol.

When to use it

Use this package when an automated performance, debugging, or auditing tool needs the same structured component and profiler data shown by the Chromium extension. The target page must already expose the eXact DevTools runtime.

Connection

Call connectExactDevtoolsAgent() with the CDP connection details for an existing Chromium target. The returned connection implements the shared inspection query service and provides disconnect() for cleanup. With an existing page target's WebSocket URL:

import { connectExactDevtoolsAgent } from '@exactjs/devtools-agent';

const connection = await connectExactDevtoolsAgent({
	webSocketUrl: 'ws://127.0.0.1:9222/devtools/page/REPLACE_WITH_TARGET_ID'
});
try {
	const response = await connection.request({
		protocol: 1,
		id: 'inspect-roots',
		method: 'roots.list',
		params: { page: { limit: 20 } }
	});
	if (!response.ok) throw new Error(`${response.error}: ${response.reason ?? ''}`);
	console.log(response.result);
} finally {
	await connection.disconnect();
}

The URL identifies a page in a Chromium instance with remote debugging already available. Query session.describe for capabilities, then follow a root through components.tree and components.get. Preserve returned runtime identities when querying state.get, tasks.list, dependencies.explain, or errors.list. The installed @exactjs/devtools-protocol declarations specify each request and result. Collection responses may include a continuation cursor.

An unavailable hook or denied query is an inspection failure, not an empty application. After navigation or session expiration, discover the new roots and identities. Close any subscription handles before disconnecting.

The adapter uses fixed CDP functions and validated by-value arguments. It cannot invoke component work, mutate state, widen redaction, request unbounded data, or evaluate caller-provided JavaScript.

Connection establishment, target discovery, and individual CDP requests are time-bounded. Target discovery responses, WebSocket messages, and the number of pending requests are bounded as well. Advanced callers may tune these ceilings with ExactCdpConnectionOptions and cancel work with an AbortSignal.

Documentation | Source on GitHub