Nock allow connections to servers that the current process start them

nock-allow-single-port.ts

import nock from 'nock';
import { Server } from 'http';

const kHttpServerListen = Symbol('kHttpServerListen');
const openServerPorts = new Set<number>();

function allowRemoteHttpRequestsOnlyToOurServer() {
	nock.disableNetConnect();

	nock.enableNetConnect(host => {
		let hostAsUrl: URL;

		// If having protocol
		if (/^[\w\d]+:\/\//m.test(host)) {
			hostAsUrl = new URL(host);
		} else {
			// noinspection HttpUrlsUsage - disable webstorm want the protocol to be https
			hostAsUrl = new URL(`http://${host}`);
		}

		let port = hostAsUrl.port;

		// Setting the value to the default port of the url protocol will result in the port value becoming the empty string ('')
		// From https://nodejs.org/api/url.html#urlport
		if (port === '') {
			switch (hostAsUrl.protocol) {
				case 'http':
					port = '80';
					break;
				case 'https':
					port = '443';
					break;
			}
		}

		return openServerPorts.has(parseInt(port));
	});

	// Override http server listen request so we could enable http requests to our HTTP server

	// Using symbol to make sure we don't override existing methods
	(Server.prototype as any)[kHttpServerListen] = Server.prototype.listen;
	Server.prototype.listen = function(...args) {
		const listenResult = (this as any)[kHttpServerListen](...args);
		const listenedPort = listenResult.address().port;

		openServerPorts.add(listenedPort);

		listenResult.once('close', () => openServerPorts.delete(listenedPort));

		return listenResult;
	};
}

beforeAll(() => {
	allowRemoteHttpRequestsOnlyToOurServer();
})

afterAll(() => {
	Server.prototype.listen = (Server.prototype as any)[kHttpServerListen];
})