A library for setting up server-sent events in Node.js. This library was inspired by work done by Dino Paskvan on express-sse
npm
npm install server-events-nodejs --save
yarn
yarn add server-events-nodejs
const { Source, EventStream } = require('server-events-nodejs');
const express = require('express');
const cuid = require('cuid');
const port = "8080";
const source = new Source(cuid);
const app = express();
app.listen(port, () => {
console.log('Server ready!');
});
app.use(
EventStream.init(source, {
no_ids: false, // if you need id: key/value (from the cuid lib) as part of the text-stream response - set to 'true'
pad_for_ie: false, // if the HTTP request is from an IE 8/9 browser - set to 'true'
prefered_event_name: 'update', // if you need event: key/value (here set to 'update') as part of the text-stream resposne - set here to whatever you like
prefer_event_name: true // enforce the prefered event name to be used in the text-stream response
})
);
app.get('/notifications', function(req){
console.log('headers: ', req.headers);
// send comment: '!this is a comment!'
// send with event name: 'update'
// send with retry: 4500 (4.5 seconds)
source.send({
ids: [ '123', '456' ],
timestamp: Date.now()
},
'!this is a comment!', // comment
'update', // event
4500 // retry
);
});Then, you need to setup the front-end accordingly
const evtSource = new EventSource('http://localhost:8080/notifications');
evtSource.addEventListener('open', function(e) {
console.log("connection is open!");
}, false);
evtSource.addEventListener('error', function(e) {
console.error(e);
evtSource.close();
})
evtSource.addEventListener('update', function(e) {
console.log("message: ", JSON.parse(e.data));
}, false);
/* - logs to console -
connection is open!
message: {
"ids": [
"123",
"456"
],
"timestamp": 1608970168797
}
*/MIT