How to save multidimensional pseudoArray to localstorage

My array:

state = [
[ "depth":0,
  "id":1,
  "desc":"something",
  "prof": [ 
    ["ID":1, "ID_ZASOB":1],
    ["ID":5, "ID_ZASOB":4] 
    ] 
],
[ "depth":2,
  "id":3,
  "desc":"somethingOther",
  "prof": [ 
    ["ID":2, "ID_ZASOB":5],
    ["ID":2, "ID_ZASOB":1]
    ] 
],
]

And I have to store it in localstorage.

I tried json.stringify, but this is not an object, it's an array,