Node.js app works locally but heroku says missing module

Question

I made a simple chat application using Node.JS and Socket.IO, everything works fine locally, but when I push it to heroku it gives me an application error, when I check the logs, this is the error:

Error: Cannot find module 'indexof'
    at Function.Module._resolveFilename <module.js:338:15>
    at Function.Module._load <module.js:280:25>
    at Module.require <module.js:364:17>
    at require <module.js:380:17>
    at Object.<anonymous> </app/node_modules/socket.io/node_modules/socket.io-parser/node_modules/emitter/index.js:6:13>
    at Module._compile <module.js:456:26>
    at Object.Module._extensions..js <module.js:474:10>
    at Module.load <module.js:356:32>
    at Functin.Module._load <module.js:312:12>
    at Module.require <module.js:364:17>

So I figured out that indexof is a module that Socket.IO uses, and it is in my node_modules folder, but for some reason either it's not being pushed to heroku or it's just not being recognized. I reinstalled my modules 5-6 times and recreated the app but it's still giving me the same error. My package.json file has 3 dependencies: Express, Socket.IO and Jade

Answer 1

Alright so after 2 hours I figured the problem out, multiple folders named "emitter" that contained the indexof module also had a gitignore file that made git ignore the module, no idea why that was even there, but deleting them fixed the problem