@loopeco/socketio/src/express.ts

A enhanced LoopBack's WebSocket server based on socket.io

import {Socket} from 'socket.io';
import {IncomingMessage, OutgoingMessage} from 'http';
import express from 'express';
import {SocketIoNextFunction} from './types';
import setPrototypeOf = require('setprototypeof');

export function expressInit(socket: Socket, next?: SocketIoNextFunction): [express.Request, express.Response];
export function expressInit(
  request: IncomingMessage,
  response?: OutgoingMessage | SocketIoNextFunction,
  next?: SocketIoNextFunction,
): [express.Request, express.Response];
export function expressInit(
  request: IncomingMessage | Socket,
  response?: OutgoingMessage | SocketIoNextFunction,
  next?: SocketIoNextFunction,
): [express.Request, express.Response] {
  if (typeof (request as Socket).use === 'function') {
    request = (request as Socket).request;
  }
  if (typeof response === 'function') {
    next = response as SocketIoNextFunction;
    response = undefined;
  }

  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const req = (request ?? {}) as any;
  // eslint-disable-next-line @typescript-eslint/no-explicit-any
  const res = (response ?? req.res ?? {}) as any;

  if (!req.res) req.res = res;
  if (!res.req) res.req = req;
  req.next = next;

  if (!isExpressRequest(req)) setPrototypeOf(req, express.request);
  if (!isExpressResponse(res)) setPrototypeOf(res, express.response);
  return [req, res];
}

export function isExpressRequest(x?: object): x is express.Request {
  return !!x && typeof (x as express.Request).header === 'function';
}

export function isExpressResponse(x?: object): x is express.Response {
  return !!x && typeof (x as express.Response).header === 'function';
}