Tiny EventSource

Tiny EventSource simplifies server-sent events for API servers.

Example

Using the factory

import {eventsource} from "tiny-eventsource";
import {STATUS_CODES} from "node:http";

const streams = new Map();

export function stream (req, res) {
	if (req.isAuthenticated()) {
		const id = req.user.id;

		if (!streams.has(id)) {
			streams.set(id, eventsource({ms: 2e4}, "connected"));
		}

		streams.get(id).init(req, res);
	} else {
		res.statusCode = 401;
		res.writeHead(res.statusCode, {headers: {"cache-control": "no-cache, must re-validate"}})
		res.end(STATUS_CODES[res.statusCode]);
	}
};

Using the Class

import {EventSource} from "tiny-eventsource";

Testing

Tiny EventSource has 100% code coverage with its tests.

  Testing functionality
    ✔ It should do nothing with stock configuration
    ✔ It should have an accurate listener count
    ✔ It should have a heartbeat (502ms)
    ✔ It should send custom events


  4 passing (508ms)

----------------------|---------|----------|---------|---------|----------------------
File                  | % Stmts | % Branch | % Funcs | % Lines | Uncovered Line #s    
----------------------|---------|----------|---------|---------|----------------------
All files             |     100 |    72.22 |     100 |     100 |                      
 tiny-eventsource.cjs |     100 |    72.22 |     100 |     100 | 35-36,49,56,66,68-88 
----------------------|---------|----------|---------|---------|----------------------

Options

event

Default is message.

ms

Default is 0. If greater than 0 a heart beat will be created from init().

msg

Default is ping. Message sent if ms is greater than 0.

Events

close

Emitted when an EventSource request is closed.

API

constructor({options}, [...msgs])

Creates an EventSource instance with optional messages to be transmitted on successful connection.

init(req, res)

Initializes an Event Source stream.

listenerCount()

Returns the number of listeners on the EventSource instance.

send(msg[, event, id]);

Sends a message over an EventSource instance.

setMaxListeners(n)

Sets the maximum listeners on the EventSource instance; default is 0.

avoidwork / tiny-eventsource