EventSource

This is a custom EventSource implementation that is fully compliant with the WHATWG Server-Sent Events specification but takes more arguments like request headers.

It can be used in both web and Node.js environments.

The motivation for this library is that the native browser EventSource does not offer options for changing the request that is sent to the server. This means that e.g. you can not send an authorization header. This is fixed by this library.

Features

Supports both web and Node.js environments
Follows the WHATWG Server-Sent Events specification and can be uses everywhere where the native EventSource would be
used.

Installation

Install the package using npm:

npm i extended-eventsource

Usage

The package exposes a single class called EventSource. To use it, create a new instance of EventSource with the URL of the server-sent events endpoint, and an optional configuration object.

Web

import { EventSource } from 'extended-eventsource';

const eventSource = new EventSource('/events', {
  headers: {
    Authorization: 'Bearer token',
  },
  retry: 3000,
});

eventSource.onopen = () => {
  console.log('Connection opened');
};

eventSource.onmessage = (event: MessageEvent) => {
  console.log('Message received:', event.data);
};

eventSource.onerror = (error) => {
  console.error('Error occurred:', error);
};