verdaccio/test/functional/lib/simple_server.js

// @flow
import express from 'express';
import bodyParser from 'body-parser';

export default class ExpressServer {
	app: any;
	server: any;

	constructor() {
		this.app = express();
		this.server;
	}

	start(port: number): Promise<any> {
		return new Promise((resolve, reject) => {
			this.app.use(bodyParser.json());
			this.app.use(bodyParser.urlencoded({
				extended: true
			}));

			this.server = this.app.listen(port, function starExpressServer() {
				resolve();
			});
		});
	}
}