In JSONPath, how to find keys matching a 'non existing' filter?

Question

Here is a json snippet containing a definition structure :

{
  "Type": "page",
  "Label": "Test",
  "Children": {
    "crud": {
      "Type": "crud",
      "Datasource": "crud_data",
      "Children": {
        "level1": {},
        "group": {
          "Type": "group",
          "level2": {},
          "Children": {
            "level3a": {},
            "level3b": {},
            "level3c": {}
          }
        }
      }                        
    }
  }
}

I'm trying to find a JSON expression to find every key under "Children", which do not contain any "Type" property inside.

How to say "no Type property" inside an object ?

In the example, I'm expecting this result:

[
  "level1",
  "level3a",
  "level3b",
  "level3c"
]

Note the "crud" and "group" are excluded because they define a "Type" property. Other objects are empty in the example, but could contain properties other the Type and should still match.

I imagine a solution like this : $..Children.*[?(a filter here saying no Type)]~

Thank you for your help

score 0 · Answer 1 · answered Jul 07 '23 at 09:51

For most implementations, @.Type on its own should be an existence check and can be negated with !. So this should get you most of the way there:

$..[?(!@.Type)]

The problem that this presents is that this returns every child value that doesn't have a Type property, regardless of what kind of value that is. For example, "page" doesn't have a Type property because it's not an object; it doesn't have any properties. But you only want objects.

But JSON Path doesn't have a way to isolate a particular kind of value.

If you were to take the result of this path and then filter for objects, you should get what you want.

In JSONPath, how to find keys matching a 'non existing' filter?

1 Answers1