node.js - Nodejs exception escapes the try/catch block -

var http = require('http');  console.log("subscriberservice.prototype.subscribe("+json.stringify(subscriber)+")");  var options = {     host: 'my host goes here',     path: 'path goes here',     port: '3030',     method: 'put',     headers: {'content-type': "application/json", 'connection': "close"} };  /*  * defines callback executed once http request executed , response received  */ var internalcallback = function(response) {      console.log('status: ' + response.statuscode);     console.log('headers: ' + json.stringify(response.headers));     response.setencoding('utf8');       var str = '';     response.on('data', function (chunk) {         str += chunk;     });      response.on('end', function () {          if(response.statuscode == 201 || response.statuscode == 200) {             console.log("success, created new subscriber: " + str);             console.log("executing subscriber service success callback");             callback(str);         }         else {             console.log("error, ["+response.statuscode+"] failed create subscriber: " + new error(str));             console.log("executing subscriber service error callback");             errorcallback(new error(str), response.statuscode);         }     });      response.on('error', function(e) {         console.log("error, failed create subscriber: " + e);         console.log("executing subscriber service error callback");         errorcallback(e, 500);     }); };  try {      console.log("executing subscriber put request: dto = " + json.stringify(subscriber));     var req = http.request(options, internalcallback);      /*      * actual send call executes actual http request subscriber service      */     req.write(json.stringify(subscriber));     req.end(); } catch(error) {      console.error("failed send request subscriber service: " + error.message);     errorcallback("failed send request subscriber service: " + error.message, 500); } 

thats code. however, if resource trying connect isnt available or there sort of connection issue exception escapes try/catch , gets caught unhandled exception handler.

i totally confused why. looked through documentation http module , can't figure out. how handle connection errors gracefully.

this error (if resource isn't available , refuses connection)

    #sending subscribe request subscriber service: [{"firstname":"","lastname":"","email":"f","ip":"127.0.0.1"}] subscriberservice.prototype.subscribe({"firstname":"","lastname":"","email":"f","ip":"127.0.0.1"}) executing subscriber put request: dto = {"firstname":"","lastname":"","email":"f","ip":"127.0.0.1"}  events.js:72         throw er; // unhandled 'error' event               ^ error: connect econnrefused     @ errnoexception (net.js:904:11)     @ object.afterconnect [as oncomplete] (net.js:895:19) 

just in example in documentation, should handle errors this:

req.on('error', function(e) {   console.log('problem request: ' + e.message); }); 

errors or exceptions in asynchronous operations not caught try/catch @ higher level. so, have handled separately this.