jq filter: show whole structure with selection

Question

I have following file1 json:

{
  "name": "eye",
  "attributes": [
    {
      "name": "Width",
      "value": "1920"
    },
    {
      "name": "Height",
      "value": "1080"
    },
    {
      "name": "WinKeyMapping",
      "value": "leftwin"
    }
  ],
  "starts": [
    {
      "name": "step1",
      "attributeList": [
        {
          "name": "Command",
          "value": "bash"
        },
        {
          "name": "Test",
          "value": "none"
        }
      ]
    }
  ]
}

and following filter:

$ jq '.starts[].attributeList[]|select(.name=="Command")' file1
{
  "name": "Command",
  "value": "bash"
}
$

how could I get whole structure to this selection?

expected output:

{
  "starts": [
    {
      "attributeList": [
        {
          "name": "Command",
          "value": "bash"
        }
      ]
    }
  ]
}

Answer 1

Straightforwardly with jq:

jq '{ starts: [ { attributeList: (.starts[].attributeList 
                                  | map(select(.name == "Command"))) }] }' file.json

The output:

{
  "starts": [
    {
      "attributeList": [
        {
          "name": "Command",
          "value": "bash"
        }
      ]
    }
  ]
}

Answer 2

Here are two options to obtain your desired output.

You can delete the keys you don't want:

jq 'del(.attributes, .name) | 
  .starts[].attributeList = map(.[].attributeList[] | select(.name == "Command"))'

Or you can select only the key(s) you do want:

jq 'to_entries | map(select(.key == "starts")) | from_entries | 
  .starts[].attributeList = map(.[].attributeList[] | select(.name == "Command"))'

Both give the same result. Also if you wanted starts and ends in the latter case, you could just add additional or statements: map(select((.key == "starts") or (.key == "ends"))).

Answer 3

A more generic approach with jq:

def pick_out(q): path(q) as $path | ($path | length) as $length |
    delpaths(
        [
            paths(..) |
            select(length <= $length and $path[0:length] != . )
        ]
    );

This is a jq function that deletes all the paths of the document that does not lie anywhere on the path of the given argument, which may be a select() call.

Saving this in pick_out.jq, we may use it like so:

jq 'include "pick_out";
    pick_out(
        .starts[].attributeList[] | select(.name == "Command")
    )' file.json

The output:

{
  "starts": [
    {
      "attributeList": [
        {
          "name": "Command",
          "value": "bash"
        }
      ]
    }
  ]
}