Set variables from javascript (object)

im in need to link my js code with app connect
i know about the hidden inputs way. but i dont want to use it since its not practical in m situation. (having 30+ inputs is absurd)
im using framework7 to build a mobile app and there is a lot of data i need to pass from my code to app connect. and vice versa, some are strings and some are objects.

how can i set a variable value from js? what function i need to call?

Thank you!