Node.js proxy round robin distribution

const http = require("http");
const URL = require("url");
/*Function createRoundRobinProvider(port,proxies)
    Creates a Round Robin Distributing Server that Devides the Requests to the Proxies

    Parameters:
        port        - The port the server uses
        proxies     - The proxies in an array of host-port objects [{host:"host",port:0},{host:"host",port:1}]...

    Returns:
        trus

    Events:
        request     - fired on incomming request, returns the request and the relay Proxy
        response    - fired on outgoing proxy response, returns the response and the relay Proxy
*/
function proxyDistributior(port,proxies){
    this.proxy_index = 0;
    self = this;
    http.createServer((request,response)=>{
        if(self.proxy_index >= proxies.length){self.proxy_index = 0;}
        var proxy = proxies[self.proxy_index++];
        self.emit("request",request,proxy);
        console.log(request.url)
        var proxy_request = http.request({
            host:proxy.host,
            port:proxy.port,
            path:URL.parse(request.url).path,
            method:request.method,
            headers:request.headers
        },(proxy_response)=>{
            self.emit("response",proxy_response,proxy);
            proxy_response.on('data',(chunk)=>{
                response.write(chunk);
            });
            proxy_response.on('end',_=>{
                response.end();
            });
            response.writeHead(proxy_response.statusCode,proxy_response.headers);
        });
        request.on('data',(chunk)=>{
            proxy_request.write(chunk);
        });
        request.on('end',_=>{
            proxy_request.end();
        });
    }).listen(port);
    return this;
}
util.inherits(proxyDistributior,require("events").EventEmitter);

this.proxyDistributor= proxyDistributior;