node_modules/sockjs-client/lib/transport/jsonp-polling.js

'use strict';

// The simplest and most robust transport, using the well-know cross
// domain hack - JSONP. This transport is quite inefficient - one
// message could use up to one http request. But at least it works almost
// everywhere.
// Known limitations:
//   o you will get a spinning cursor
//   o for Konqueror a dumb timer is needed to detect errors

var inherits = require('inherits')
  , SenderReceiver = require('./lib/sender-receiver')
  , JsonpReceiver = require('./receiver/jsonp')
  , jsonpSender = require('./sender/jsonp')
  ;

function JsonPTransport(transUrl) {
  if (!JsonPTransport.enabled()) {
    throw new Error('Transport created when disabled');
  }
  SenderReceiver.call(this, transUrl, '/jsonp', jsonpSender, JsonpReceiver);
}

inherits(JsonPTransport, SenderReceiver);

JsonPTransport.enabled = function() {
  return !!global.document;
};

JsonPTransport.transportName = 'jsonp-polling';
JsonPTransport.roundTrips = 1;
JsonPTransport.needBody = true;

module.exports = JsonPTransport;