Save a specific variable from a postman array

Question

I have a postman json response and within the array the position of a specific variable changes. Based on my response below i need to write a test to loop through the response the first sighting of optionLabel with value "2 Pax Min". Save its "id" i.e BBBB in the environment variable

I have tried this

var jsonData = JSON.parse(responseBody);
jsonData[[0].optionSet.options].forEach(function(arroption) { 
if (arroption.optionLabel === '2 Pax Min') {
    pm.environment.set("pax", JSON.stringify(arroption.id));   
}
});

My Response

[
    {
        "id": "",
        "date": "2019-08-21",
        "optionSet": {
            "optionSetLabel": "Options",
            "options": [
                {
                    "id": "A",
                    "optionLabel": "QUAD Rm"
                },
                {
                    "id": "AA",
                    "optionLabel": "QUAD Rm with post Accom"
                },
                {
                    "id": "AAA",
                    "optionLabel": "Rm 3 Pax Min"
                },
                {
                    "id": "AAAA",
                    "optionLabel": "4 Pax Min"
                }
            ]
        }
    },
    {
        "id": "",
        "date": "2019-08-22",
        "optionSet": {
            "optionSetLabel": "Options",
            "options": [
                {
                    "id": "B",
                    "optionLabel": "QUAD Rm"
                },
                {
                    "id": "BB",
                    "optionLabel": "QUAD Rm with post Accom"
                },
                {
                    "id": "BBB",
                    "optionLabel": "SGL Rm with post Accom"
                },
                {
                    "id": "BBBB",
                    "optionLabel": "2 Pax Min"
                }
            ]
        }
    }
]

My end result is i want to save the id "BBBB" in the environment variable

Answer 1

Mickael's answer should be the accepted solution (I upvoted it) but I just wanted to offer the same thing done with Lodash, which is built-in to Postman.

_.each(pm.response.json(), (data) => {
    _.each(data.optionSet.options, (option) => {
        if (option.optionLabel === '2 Pax Min') {
            pm.environment.set("pax", option.id);
        }
    })
})

I see lots of answers that do this var jsonData = JSON.parse(responseBody); to parse the response body but it's the same as just using the newer pm.* API function pm.response.json() to do the same thing.

https://learning.getpostman.com/docs/postman/scripts/postman_sandbox_api_reference/

Answer 2

You have a braket problem here jsonData[[0].optionSet.options].

Maybe you wanted to do something like jsonData[0].optionSet.options or jsonData[1].optionSet.options

Here this code should do what you want

for (let data of jsonData) {
  for (let option of data.optionSet.options) {
    if (option.optionLabel === '2 Pax Min') {
      pm.environment.set("pax", JSON.stringify(option.id));
    }
  }
}

Same with forEach rather than for loop

jsonData.forEach(function(data) {
  data.optionSet.options.forEach(function(arroption) {
    if (arroption.optionLabel === '2 Pax Min') {
      pm.environment.set("pax", JSON.stringify(arroption.id));
    }
  })
})