Where does nedb store data?

Question

Database

I decided to use nedb for a small project. Checked, added a lot of test data. And decided to clean up. I cleared the .db file where all the data is stored, but after that I see that the data is still loaded, from where I don’t know. Apparently the data is stored in RAM. But why is the data stored there if I have included the file? How to clean up the database?