This application is written in Node.js, its server works with Express.js and its front-end works with ReactJS and reactstrap (Bootstrap for React). With it you can create all possible combinations of schedules based on a set of initial possible timeframes for different classes. It's available here: https://horit.herokuapp.com/ (may take a couple of seconds loading).
You can press the Test button and then Ready to see how it works, the arrow at the right of each class can be used to expand its possible schedules.
I coded this because I wanted to design a more efficient and fast way to create schedules for university. The main algorithm is in the file optimizer.js and all of the React code is inside client.