Server-Sent Events stream

Problem. Consume an SSE endpoint and render incoming events without manual EventSource plumbing.

Solution. useEventSource exposes data, eventName, error, and lifecycle controls as signals.

import { effect, useEventSource } from '@bquery/bquery/reactive';

const sse = useEventSource('/events', {
  events: ['progress', 'done'],
  autoReconnect: { delay: 1_000, maxAttempts: 5 },
});

effect(() => {
  if (sse.eventName.value === 'progress') updateBar(sse.data.value);
  if (sse.eventName.value === 'done') finish(sse.data.value);
});

Why it works. useEventSource parses JSON by default and surfaces both named events and the catch-all stream, so a single composable powers progress indicators and final-state handling.

Reactive — SSE helpers
Server — ctx.sse
Longer worked example: Examples & Recipes — Real-time communication

Server-Sent Events stream ​

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Server-Sent Events stream

Related