The site simply shows a JS code snippet which is a pattern and gives 4 options to answer the pattern that is implemented. At the end, you get to know your score.
There is also quick reference available on the site
How much did I score? I scored 17/23, but to be honest, I could only get 10-12 identification at first go, rest I just eliminated other 3 options out of 4.
All the code samples on the site are taken from this Design-Patterns-JS by Felipe Beline.