Parsing string with fromjson and collapsing into the parent in JQ - json

Question

I am attempting to parse out the following json array below. The activities object is a string and I have successfully been able to parse it out with the following in jq.
[
{
"id": 101,
"created_at": "1987-10-12 03:20:22.903",
"updated_at": "1987-10-12 01:20:36.019",
"activities": "{\"hero\": \"batman\", \"weapon\": \"sword\", \"ts\": null, \"remote\": \"1\",\"game\": \"joker\", \"image\": \"bold\"}"
},
{
"id": 102,
"created_at": "2022-10-12 11:20:22.903724",
"updated_at": "2022-10-12 11:20:36.019043",
"activities": "{\"hero\": \"superman\", \"weapon\": \"cape\", \"ts\": null, \"remote\": \"2\",\"game\": \"batman\", \"image\": \"kind\"}"
}
]
The following command allows me to parse out the string object but I haven't quite figured out how to get it back into the original array.
jq '.[].activities | fromjson?' test.json
Output:
{
"hero": "batman",
"weapon": "sword",
"ts": null,
"remote": "1",
"game": "joker",
"image": "bold"
}
{
"hero": "superman",
"weapon": "cape",
"ts": null,
"remote": "2",
"game": "batman",
"image": "kind"
}
I tried several variances of the += and |= operators to add back to the original without any luck.
jq '.[].activities |= fromjson? | select( . != "")'
Bypassed any empty values with the select command.
This yields no results for the activities object when I run it. It brings the original id, created_at, and updated_at forward but nothing else.
Appreciate any help you can offer. Thanks guys.
Preferred Output
[
{
"id": 101,
"created_at": "1987-10-12 03:20:22.903",
"updated_at": "1987-10-12 01:20:36.019",
"hero": "batman",
"weapon": "sword",
"ts": null,
"remote": "1",
"game": "joker",
"image": "bold"
},
{
"id": 102,
"created_at": "2022-10-12 11:20:22.903724",
"updated_at": "2022-10-12 11:20:36.019043",
"hero": "superman",
"weapon": "cape",
"ts": null,
"remote": "2",
"game": "batman",
"image": "kind"
}
]

Answer 1

Something like this should be enough:
map(del(.activities) + (.activities | fromjson))
Online demo

Answer 2

Here's a starting point, assigning a real JSON object to the activities key:
map(.activities |= fromjson)
Output:
[
{
"id": 101,
"created_at": "1987-10-12 03:20:22.903",
"updated_at": "1987-10-12 01:20:36.019",
"activities": {
"hero": "batman",
"weapon": "sword",
"ts": null,
"remote": "1",
"game": "joker",
"image": "bold"
}
},
{
"id": 102,
"created_at": "2022-10-12 11:20:22.903724",
"updated_at": "2022-10-12 11:20:36.019043",
"activities": {
"hero": "superman",
"weapon": "cape",
"ts": null,
"remote": "2",
"game": "batman",
"image": "kind"
}
}
]
And to merge the activities sub-object into its parent object, while deleting the old property:
map(. + (.activities | fromjson) | del(.activities))
Output:
[
{
"id": 101,
"created_at": "1987-10-12 03:20:22.903",
"updated_at": "1987-10-12 01:20:36.019",
"hero": "batman",
"weapon": "sword",
"ts": null,
"remote": "1",
"game": "joker",
"image": "bold"
},
{
"id": 102,
"created_at": "2022-10-12 11:20:22.903724",
"updated_at": "2022-10-12 11:20:36.019043",
"hero": "superman",
"weapon": "cape",
"ts": null,
"remote": "2",
"game": "batman",
"image": "kind"
}
]