Mock Server With ExpressJS, TypeScript for your API

mock-route.ts

import * as express from 'express';
import mockRoutes from './MockRoutes';
import config from '../config/Config';
import proxy = require('http-proxy-middleware');

class Routes {
  public router: express.Router = express.Router();

  constructor() {
    this.config();
  }

  private config(): void {
    this.router.get('/', (req: express.Request, res: express.Response) =>
      res.status(200).json({message: 'Welcome to the CLO Mock Server API'})
    );
    this.router.use('/v1d', proxy(this.filterProxy, {
      changeOrigin: true,
      target: config.API_URL,
      onProxyReq: (proxyReq: any, req: any, res: any) => {
        if (req.body) {
          let bodyData = JSON.stringify(req.body);
          proxyReq.setHeader('Content-Type','application/json');
          proxyReq.write(bodyData);
        }
      }
    }));
    mockRoutes.forEach(route => {
      switch (route.method) {
        case 'GET':
          this.router.get(route.pathname + '*', (req: express.Request, res: express.Response) =>
            res.status(route.status).json(route.responseBody)
          );
          break;
        case 'PUT':
          this.router.put(route.pathname + '*', (req: express.Request, res: express.Response) =>
            res.status(route.status).json(route.responseBody)
          );
          break;
        case 'POST':
          this.router.post(route.pathname + '*', (req: express.Request, res: express.Response) =>
            res.status(route.status).json(route.responseBody)
          );
          break;
        case 'DELETE':
          this.router.delete(route.pathname + '*', (req: express.Request, res: express.Response) =>
            res.status(route.status).json(route.responseBody)
          );
          break;
        default:
          break;
      }
    });
  }

  private filterProxy(pathname: string, req: express.Request) {
    return !mockRoutes.find(route =>
      pathname.indexOf(route.pathname) !== -1 && req.method.toUpperCase() === route.method.toUpperCase()
    );
  }
}

export const routes = new Routes().router;