Q:

angular-socket-io io is not defined

There was a suggestion here: https://github.com/btford/angular-socket-io/issues/127

make sure you have socket.io client library:
bower install socket.io-client --save

This didn't fix my problem with this same error.

including in index.html: 
script src="lib/angular-socket-io/socket.js"

in app.js
angular.module('starter', ['ionic', 'starter.controllers', 'starter.services',       
 'starter.directives', 'btford.socket-io'])

in services.js
.factory('seatStatusSocket',function(socketFactory){ 
   var myIoSocket = io.connect(porturl); // io is not defined here, suddenly.

It was working before, using a remote copy of the lib. When this error started, I changed index.html to link a local copy, as this remote version also received a Bad Gateway error (now fine, but still socket io is not defined as above).

removed:
script src="http://chat.socket.io/socket.io/socket.io.js"

versions
socket.io@1.3.7 node_modules/socket.io
node --version
v0.12.7

A:

You have to include in index.html:   
script src="<bowerComponentPath>/socket.io-client/socket.io.js"

before this:
script src="<bowerComponentPath>/angular-socket-io/socket.js"

and yest this is required:
bower install socket.io-client --save

