A comma is a common way to separate array items in a string. You can use the split() and join() methods to turn strings into arrays & back again. JSON.parse is definitely an option, but it does have strict some syntax required or it will throw an error. Split works like this: const hidden_attr = 'one,two,three'; let array1 = hidden_attr.split(','); // expected value of array1: ['one', 'two', 'three'] You don't have to use a comma to separate your values, it can be whatever you want (obviously a comma is inappropriate if you have actual sentences with punctuation stored in there, for example). To turn it back into a string so you can store it in a character sheet again: const array2 = ['one', 'three']; let output = array2.join(','); // expected value of output: 'one,three' If you've got a more complex structure, say an array full of objects, then you'd want to go with JSON.parse and JSON.stringify as Nic suggested. In this case, you'd probably want to start with a working array/object structure and stringify it first, so you know you have a parseable layout to manipulate. Working the other way (trying to get a linear, working JSON structure typed out in an Attribute) could be difficult.
