如何处理Node / Express / Typescript中的拒绝？

Question

我正在构建一个简单的Crud Node / Express / Typescript应用程序，但出现以下错误：

Express server listening on port 3000
(node:39970) UnhandledPromiseRejectionWarning: Error: connect ECONNREFUSED 127.0.0.1:27017
    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1113:14)
(node:39970) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 1)
(node:39970) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

服务器似乎在端口3000上运行，但实际上我无法在Postman上执行任何GET请求。我想我需要将async await与try catch处理程序一起使用，但不确定在哪里失败。

这是我的代码：

app.js

import * as express from "express";
import * as bodyParser from "body-parser";
import { Routes } from "./routes/crmRoutes";
import * as mongoose from "mongoose";

class App {
  public app: express.Application;
  public routePrv: Routes = new Routes();
  public mongoUrl: string = "mongodb://localhost/CRMdb";

  constructor() {
    this.app = express();
    this.config();
    this.routePrv.routes(this.app);
    this.mongoSetup();
  }

  private config(): void {
    this.app.use(bodyParser.json());
    this.app.use(bodyParser.urlencoded({ extended: true }));
    this.app.use(express.static("public"));
  }

  private mongoSetup(): void {
    mongoose.Promise = global.Promise;
    mongoose.connect(this.mongoUrl, {
      useNewUrlParser: true
    });
  }
}

export default new App().app;

控制器

import * as mongoose from "mongoose";
import { ContactSchema } from "../models/crmModel";
import { Request, Response } from "express";

const Contact = mongoose.model("Contact", ContactSchema);

export class ContactController {
  public addNewContact(req: Request, res: Response) {
    let newContact = new Contact(req.body);

    newContact.save((err, contact) => {
      if (err) {
        res.send(err);
      }
      res.json(contact);
    });
  }

  public getContacts(req: Request, res: Response) {
    Contact.find({}, (err, contact) => {
      if (err) {
        res.send(err);
      }
      res.json(contact);
    });
  }

  public getContactWithID(req: Request, res: Response) {
    Contact.findById(req.params.contactId, (err, contact) => {
      if (err) {
        res.send(err);
      }
      res.json(contact);
    });
  }

  public updateContact(req: Request, res: Response) {
    Contact.findOneAndUpdate(
      { _id: req.params.contactId },
      req.body,
      { new: true },
      (err, contact) => {
        if (err) {
          res.send(err);
        }
        res.json(contact);
      }
    );
  }

  public deleteContact(req: Request, res: Response) {
    Contact.deleteOne({ _id: req.params.contactId }, (err, contact) => {
      if (err) {
        res.send(err);
      }
      res.json({ message: "Successfully deleted contact!" });
    });
  }
}