“undefined is not a function”使用回调

I'm creating a twitter bot that is requesting from the same API, Wordnik, but each request is depending on the last request's results. So, I decided to try creating some code using callbacks to make sure that all of the information is returned from the API before the next function runs. I am having trouble setting it up, I have looked at many examples and I just cannot get the hang of it. (Sorry for the messy code).I'm creating a twitter bot that is requesting f