Combining all key value pairs in one using jq filter or jq play

Question

I want to transform JSON data using jq filter

Json data:

{
 "main": [
  {
   "firstKey": "ABCD",
   "id": "12345",
   "data": [
    {
     "name": "first_id",
     "value": "first_id_value"
    },
    {
     "name": "second_id",
     "value": "second_id_value"
    },
    {
     "name": "third_id",
     "value": "third_id_value"
    }
   ]
  }
 ]
}

Expected OUTPUT :

{
 "firstKey": "ABCD",
 "id": "12345",
 "data.name.first_id": "first_id_value",
 "data.name.second_id": "second_id_value",
 "data.name.third_id": "third_id_value"
}

After many trials and errors, I was near to expected output using following filter expression

[.main[]|{"firstKey", "id"},foreach .data[] as $item (0; "data.name.\($item.name)" as $a|$item.value as $b| {($a): $b})][]

Used foreach as objects under "data" are dynamic . the number of objects can differ. The output for the above expression is:

{
  "firstKey": "ABCD",
  "id": "12345"
}
{
  "data.name.first_id": "first_id_value"
}
{
  "data.name.second_id": "second_id_value"
}
{
  "data.name.third_id": "third_id_value"
}

But I want the objects of data to be under the same braces as 'firstKey' and 'id'.

LINK to JqPlay

Any suggestions will be helpful.

Answer 1

Since your structure is so rigid, you can cheat and use the built-in from_entries , which takes a list of {key, value} pairs and constructs an object:

.main[] |
{firstKey, id} +
  (.data | map({key: "data.name.\(.name)", value}) |
   from_entries)