sed remove json suboject from a json string - json

Question

I try to preprocess a JSON file and want to remove all subobjects in it.
Note that my JSON string is inline (not have \r).
In input I have:
{
"total": 2,
"result": [
{
"id":1,
"createdOn" : 123456,
"obj1": {
...:...,
...:...
},
"obj2": {
...:...,
...:...
},
"otherattribute": "..."
},
{
"id":2,
"createdOn" : 123456,
"obj1": {
...:...,
...:...
},
"obj2": {
...:...,
...:...
},
"otherattribute": "..."
}
]
}
And want to have:
{
"total": 2,
"result": [
{
"id":1,
"createdOn" : 123456,
"otherattribute": "..."
},
{
"id":2,
"createdOn" : 123456,
"otherattribute": "..."
}
]
}
I've tried to use sed command with :
sed 's/"obj1":{[^}]*//g'
It will remove the "ojb1" subobject, but let remain the endind "}," of this subobject.
I didn't find the way to also remove "},".
How?
Second question: I know the list of suboject; but is there a way to remove all theses subjects directly without knowing there name? Something like:
sed 's/".*":{[^}]*//g'
So that I will have only one sed command and not having to chain commands like :
sed 's/obj1//g' | sed 's/obj2//g' | sed 's/obj3//g' ...

Answer 1

I'm giving a first answer:
sed 's/"obj1":{[^}},]*//g'
It will match "obj1": until character } and then match again },, so that these last 2 chars will be also deleted (replaced with nothing).
Now I try to do something more generic to match any object name, with something like this:
sed 's/"[[:alnum:]]":{[^}},]*//g'
But it's not working...
I've already tried to escape or escape escape or escape escape escape double quote without success...