Why can't I get all variables of an object with a script(Sprite.LocalVars) in a text?

I'm trying to create json files with all the information of my layouts and create others automatically.

I have to acquire all the data regarding the variables of all the sprites, now I have this problem:

If I do: console.log(Sprite.InstVars) I get an output (like in the screenshots).

But I can't get the variables any other way.

if I do:

Sprite.LocalVars.variablename

I get that variable, but I want to use .localvars because I need to get all

and how many there are.