Use If condition in Karate to extract values

Question

I have the following JSON response -

    {
        "type": "StudentSchema",
        "version": 1,
        "students": [
            {
                id: 1,
                name: "John",
                roll: "1234"
            },
            {
                id: 2,
                name: "David",
                roll: "4434"
            }
        ]
}

Then how can I extract the array in Karate with name John to do further validation? e.g. I want to say if name == John then save the id

I am trying below but it does not seem to work -

* def userId =  get[0] response $[?(@students.name == 'John')].id
* match userId == 2

Answer 1

Let say your JSON is

MyJson =  {
    "type": "StudentSchema",
    "version": 1,
    "students": [
        {
            id: 1,
            name: "John",
            roll: "1234"
        },
        {
            id: 2,
            name: "David",
            roll: "4434"
        }
    ]
}

Now as you want to get the ID for the student whose name is john you can get it by using JSON path

* def JSONpath = '$..students[?(@.name=='John')].id'
* def userId = karate.jsonPath(MyJson,JSONpath)

It will give you an array of ID which satisfy the json path condition and you can do your assertion from that.