When building your Political Tracking app, you will be completely reliant upon a third-party API for the data. We recommend using the free Sunlight Congress API (their documents mention the need for an API key, but this is no longer required).
But first things first...
Start by understanding the API. Make a list of the data you need and then read the Sunlight Congress API documentation and take note of which endpoints and query parameters seem useful. Ideally, you should make as few API hits and retrieve as little data as possible. The more thought you put into this, the easier it will be to write the functions wrapping and processing the data.
Once you know what you want and how to retrieve it, it's time to encode that knowledge into your program. Here's is where you'll create a Node.js module full of helpful functions. You should have at least the following behavior:
Once you're done, continue to the next exercise, where you will use your new functions to turn the data into a web application.