Nobody here is going to give you a solution. We will give hints and try and guide you to answers. The point is you should be learning these things. Us giving you the answer is not helping you solve these problems and making you better at coding.
The thing is should tracks be a variable? If you look at the arguments being sent to the function it should give you a hint as to what type of data tracks should be if your are comparing it to prop. What type of data is prop holding? What type of data are property names in an object?
You have other problems with your code, but solve that first and keep asking questions and we will help.