continue to deal the result as a array after filter

[NingGelin]

Motivation

I have a json like this:

{
  "contactMedium": [
    {
      "@type": "EmailContactMedium",
      "preferred": true,
      "contactType": "other",
      "validFor": {
        "startDateTime": "2018-10-22T08:31:52.028Z"
      },
      "emailAddress": "tom@email.com"
    },
    {
      "@type": "GeographicAddressContactMedium",
      "preferred": true,
      "contactType": "other",
      "validFor": {
        "startDateTime": "2018-10-22T08:31:52.028Z"
      },
    }
  ]
}

I want to get the number of item with preferred==true
const result = JSONPath({ path: '$.contactMedium[?(@.preferred==true)].length', json: data })

Current behavior

got []

Desired behavior

got 2

Alternatives considered

currently, i can got the result expected by this way.
const result = JSONPath({ path: '$.contactMedium[?(@.preferred==true)]', json: data })
console.log(result)

const result2 = JSONPath({ path: '$.length', json: result })
console.log(result2)

[gerad]

+1 to this issue. I think I can get my company to sponsor the fix (depending on the cost).

[80avin]

@NingGelin I am not able to understand the use-case.

Why can't we use something like

const data = {
  "contactMedium": [
    {
      "@type": "EmailContactMedium",
      "preferred": true,
      "contactType": "other",
      "validFor": {
        "startDateTime": "2018-10-22T08:31:52.028Z"
      },
      "emailAddress": "tom@email.com"
    },
    {
      "@type": "GeographicAddressContactMedium",
      "preferred": true,
      "contactType": "other",
      "validFor": {
        "startDateTime": "2018-10-22T08:31:52.028Z"
      },
    }
  ]
}
const result = JSONPath({ path: '$.contactMedium[?(@.preferred==true)]', json: data }).length

[brettz9]

I think the use case would be for applications which exposed JSONPath expressions to users, and to allow the users to make a query which performed a count.

We should probably not be making custom additions to the JSONPath standard now though, so I would discuss any new proposals (e.g., for a count function) with the standards-making body if there is not already one in effect.