Application state

I’m trying to make an application that interactively creates plots. So, the user adds a new plot and customizes it for some number of times.

Obvious idea was to create a list and store objects for plots (plot name, some description and values) in it. When a user presses “Add new plot”, some sliders for customisation appear. Then, when a user presses “Plot”, I append new data to a list. But, after it, page rerenderes, and the list returns to the initial empty state.

Is there any healthy way to overcome it without saving application state into a file manually?