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Basic Connection ​

Problem ​

You need one typed session whose messages are sent only after the transport is ready and whose lifecycle can be cleaned up deterministically.

Solution ​

Subscribe before connecting, then await connect() before sending.

ts
import { createPulse } from '@vielzeug/pulse';

type ServerEvents = { 'chat:message': { text: string } };
type ClientEvents = { 'chat:send': { text: string } };

const pulse = createPulse<ServerEvents, ClientEvents>('wss://api.example.com/ws', {
  onError: (error) => console.error(error),
  reconnect: true,
});

const stop = pulse.on('chat:message', ({ text }) => console.log(text));

try {
  await pulse.connect();
  pulse.send('chat:send', { text: 'Hello!' });
} catch (error) {
  console.error('Pulse connection failed:', error);
}

stop();
pulse.dispose();

Pitfalls ​

  • Construction does not connect. Always await connect() before sending.
  • Sends do not buffer. Disconnected sends throw PulseConnectionError.
  • disconnect() cancels retries. Call connect() again to begin a new session.