Sharing socket.io between modules in typescript - node.js

Question

I have read several examples of different ways to share a socket.io connection among modules, but I can't quite seem to put all the pieces together to architect this.
I have a SocketConnection class which I want to share among all of my code.
import * as sio from 'socket.io';
export class SocketConnection {
private static instance: SocketConnection;
server: any;
private constructor(server) {
this.server = server;
}
static getInstance(server) {
if (!SocketConnection.instance) {
SocketConnection.instance = new SocketConnection(server);
const io = sio(server);
io.on('connection', (socket) => {
console.log('conncted sockets');
socket.emit('jobResult', { result: 'emitting startup!' });
});
}
return SocketConnection.instance;
}
}
Then in my app.ts, I use it like this:
// app.ts
// express app
const server = app.listen(param);
import { SocketConnection } from './integrationJobs/socketConnection';
const io = SocketConnection.getInstance(server);
// Now pass the resulting "io" into the job where I need to use socket.io
import { CourseListJob } from './integrationJobs/courseList';
const courseListJob = new CourseListJob(io);
const job = courseListJob.runJob();
Last bit of code where I call the job needing a socket:
// courseList.ts
export class CourseListJob {
io: any;
public constructor(io) {
this.io = io;
}
public async runJob() {
this.io.emit('progressMessage', 'Hello');
}
}
Unfortunately, I get this:
TypeError: this.io.emit is not a function
What am I doing wrong?

Answer 1

I solved this by modifying my SocketConnection class to this:
import * as sio from 'socket.io';
export class SocketConnection {
private static instance: SocketConnection;
server: any;
private constructor(server) {
this.server = server;
}
public static GetSocket(server) {
const io = sio(server);
io.on('connection', (socket) => {
console.log('conncted SocketConnection sockets');
socket.emit('jobResult', { result: 'emitting startup!' });
});
return io;
}
}
The in my app.ts, I use it like this:
import { SocketConnection } from './integrationJobs/socketConnection';
const io = SocketConnection.GetSocket(server);
import * as courseList from './integrationJobs/courseList';
courseList.register(io);
import * as courseEnrollment from './integrationJobs/courseEnrollment';
courseEnrollment.register(io);
In any bit of code where I need a socket, I just do this:
import * as sio from 'socket.io';
let io = null;
export function register(foo) {
io = foo;
}
export class CourseListJob {
public async runJob() {
}
}