Parsing nested JSON and creating new keys with jq - jq

Question

I have a JSON file that has hundreds of objects. Each object has 2 keys with nested object\arrays one for assignee and another for epics.
[
{
"id": 1111111111,
"assignee": {
"id": 1234,
"firstName": "John",
"lastName": "Doe",
"email": "Doe#doe.com",
},
"epics": [
{
"id": 111,
"title": "Big Code Issues",
"version": 16
}
],
"location": "Nerdville"
}
]
from the current assignee key. I want to create a two new keys assigneeId and assigneeName. Where the assigneeName is the firstName and lastName combined. The original nested assignee key can be discarded.
from the epics key I would like to create and epicsID key with a value of id from epics. The rest of the keys in the nested key can be discarded.
I am very new to jq but i would like to create following output.
[
{
"id": 1111111111,
"assigneeId": 1234,
"assingeeName": "John Doe",
"epicsid": 111,
"location": "Nerdville"
}
]
I can create and remove keys with JQ but I am have not been able to iterate the JSON file to grab values from with the nested keys and put into new keys. I have been getting errors based on different command I been running but the main one is "Cannot index array with string "epics"".
Any help would be greatly appreciated

Answer 1

After fixing a very small technical problem with your JSON, the following produces the required result:
map( {id,
assigneeId: .assignee.id,
assigneeName: (.assignee | .firstName + " " + .lastName),
epicsid: .epics[0].id,
location } )
You might wish to modify this if the "epics" array has more than one item in it.