DefinitelyTyped/types/http-proxy/http-proxy-tests.ts

import * as http from "http";
import HttpProxy = require("http-proxy");

const proxy = new HttpProxy({
  changeOrigin: true
});

proxy.on("error", (err) => {
  console.error("An error occured:", err);
});

/**
 * Test type inference of event listener parameters:
 */
proxy.on("start", (req, res, target) => {
  const headers = req.headers; // defined;
  const status = res.statusCode; // defined;
  const partial =
    typeof target === "string"
      ? target.substr(0) // defined;
      : target.protocol; // defined;
});

http.createServer((req, res) => {
  proxy.web(req, res);
});

const newProxy = HttpProxy.createProxyServer({
    target: {
        host: 'localhost',
        port: '9015'
    },
    ws: true
});