Angular Universal server rendering WebSocket - node.js

Question

Are there any examples of Angular Universal with WebSockets?
Serverside rendering does not know wat a WebSocket object is in my case. And if I use socket.io the node server hangs when trying to make a connections.
Some additional information about the problem:
I downloaded angular-universal-starter from github: https://github.com/angular/universal-starter
Which works fine out of the box running 'npm install' and 'npm start'
But after i added the following code to AppComponent
export class AppComponent implements OnInit {
ngOnInit() {
let webSocket = new WebSocket("----server url----")
}
}
I got the following error in my NodeJs server console:
EXCEPTION: WebSocket is not defined
ORIGINAL STACKTRACE:
ReferenceError: WebSocket is not defined
at AppComponent.ngOnInit (/Volumes/Development/cacadu/website/universal-starter-master2/dist
/server/index.js:41725:29)

Answer 1

Try only calling the websocket on the Client, for example you can detect whether it's the browser or the server with these imports
import { isPlatformBrowser } from '#angular/common';
import { Inject, PLATFORM_ID } from '#angular/core';
Then use them inside your code, this might be able to fix the problem!
#Component({ ... })
export class AppComponent implements OnInit {
private isBrowser: boolean = isPlatformBrowser(this.platformId);
constructor(
#Inject(PLATFORM_ID) private platformId: Object
) {
if (isBrowser) {
let webSocket = new WebSocket("----server url----");
}
}
}