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Complex JSON obj and jQuery or Javascript map to specific key, value

I am banging my head trying to figure this out. And it should not be this hard. I am obviously missing a step.
I am pulling data from: openaq.org
The object I get back is based on a JSON object.
For now, I am using jQuery to parse the object and I am getting to the sub portion of the object that hold the specific parameter I want but I can't get to the specific key,value pair.
The object does not come back in the same order all the time. So when I tried to originally set up my call I did something like
obj.results.measurements[0].
Well since the obj can come back in an random order, I went back to find the key,value pair again and it was the wrong value, throwing my visual off.
That said, I have looked at use jQuery's find() on JSON object and for some reason can not get what I need from the object I am given by openaq.org.
One version of the object looks like this:
{"meta":{"name":"openaq-api","license":"CC BY 4.0d","website":"https://u50g7n0cbj.execute-api.us-east-1.amazonaws.com/","page":1,"limit":100,"found":1},"results":[{"location":"Metro Lofts","city":null,"country":"US","coordinates":{"latitude":39.731,"longitude":-104.9888},"measurements":[{"parameter":"pm10","value":49.9,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"},{"parameter":"pm1","value":24,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"},{"parameter":"um100","value":0,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"um025","value":0.28,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"um010","value":4.1,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"pm25","value":41.1,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"}]}]}
I am trying to get the "pm25" value.
The code I have tried is this:
function getAirQualityJson(){
$.ajax({
url: 'https://api.openaq.org/v2/latest?coordinates=39.73915,-104.9847',
type: 'GET',
dataType: "json"
// data: data ,
}).done(function(json){
console.log("the json is" + JSON.stringify(json));
console.log("the json internal is" + JSON.stringify(json.results));
var obj = json.results;
var pm25 = "";
//console.log(JSON.stringify(json.results.measurements[0]["parameter"]));
$.each(json.results[0], function(i,items){
//console.log("obj item:" + JSON.stringify(obj[0].measurements));
$.each(obj[0].measurements, function(y,things){
//console.log("each measurement:" + JSON.stringify(obj[0].measurements[0].value));//get each measurement
//pm 2.5
//Can come back in random order, get value from the key "pm25"
// pm25 = JSON.stringify(obj[0].measurements[2].value);
pm25 = JSON.stringify(obj[0].measurements[0].value);
console.log("pm25 is: " + pm25); // not right
});
});
//Trying Grep and map below too. Not working
jQuery.map(obj, function(objThing)
{ console.log("map it 1:" + JSON.stringify(objThing.measurements.parameter));
if(objThing.measurements.parameter === "pm25"){
// return objThing; // or return obj.name, whatever.
console.log("map it:" + objThing);
}else{
console.log("in else for pm25 map");
}
});
jQuery.grep(obj, function(otherObj) {
//return otherObj.parameter === "pm25";
console.log("Grep it" + otherObj.measurements.parameter === "pm25");
});
});
}
getAirQualityJson();
https://jsfiddle.net/7quL0asz/
The loop is running through I as you can see I tried [2] which was the original placement of the 'pm25' value but then it switched up it's spot to the 3rd or 4th spot, so it is unpredictable.
I tried jQuery Grep and Map but it came back undefined or false.
So my question is, how would I parse this to get the 'pm25' key,value. After that, I can get the rest if I need them.
Thank you in advance for all the help.

You can use array#find and optional chaining to do this,
because we are using optional chaining, undefined will be returned if a property is missing.
Demo:
let data = {"meta":{"name":"openaq-api","license":"CC BY 4.0d","website":"https://u50g7n0cbj.execute-api.us-east-1.amazonaws.com/","page":1,"limit":100,"found":1},"results":[{"location":"Metro Lofts","city":null,"country":"US","coordinates":{"latitude":39.731,"longitude":-104.9888},"measurements":[{"parameter":"pm10","value":49.9,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"},{"parameter":"pm1","value":24,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"},{"parameter":"um100","value":0,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"um025","value":0.28,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"um010","value":4.1,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"pm25","value":41.1,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"}]}]}
let found = data?.results?.[0]?.measurements?.find?.(
({ parameter }) => parameter === "pm25"
);
console.log(found);

You can iterate over measurements and find the object you need:
const data = '{"meta":{"name":"openaq-api","license":"CC BY 4.0d","website":"https://u50g7n0cbj.execute-api.us-east-1.amazonaws.com/","page":1,"limit":100,"found":1},"results":[{"location":"Metro Lofts","city":null,"country":"US","coordinates":{"latitude":39.731,"longitude":-104.9888},"measurements":[{"parameter":"pm10","value":49.9,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"},{"parameter":"pm1","value":24,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"},{"parameter":"um100","value":0,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"um025","value":0.28,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"um010","value":4.1,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"particles/cm³"},{"parameter":"pm25","value":41.1,"lastUpdated":"2021-08-09T20:49:38+00:00","unit":"µg/m³"}]}]}';
const json = JSON.parse(data);
let value = null;
const measurements = json?.results?.[0]?.measurements ?? null;
if(measurements)
for (const item of measurements)
if (item.parameter === 'pm25') {
value = item.value;
break;
}
if (value) {
// here you can use the value
console.log(value);
}
else {
// here you should handle the case where 'pm25' is not found
}

How to parse jsonArray correctly in js?

I have json array from Json object in js like :
let jsonObject = JSON.parse(response);
let jsonArray = jsonObject.items;
When I'm trying to parse it as array using
jsonArray.map((item)=>{
console.warn(item.name); // also I tried with for loop like jsonArray[i].name
})
I got error like TypeError: Cannot read property.
But in jsonArray I have element with key name. Also when I'm trying print as jsonArray[0].name it works fine!
Example of jsonArray (Json objects on jsonArray is not same):
[
{
"name":"SomeNameHere",
"secondKey":"secondValue"
},
{
"type":"typeValue",
"secondType":"typeValue",
},
{
"name":"SomeNameHere",
"secondKey":"secondValue"
},
{
"type":"typeValue",
"secondType":"typeValue",
}
]
If it important I used Mac OS Mojave, and running react-native run-android on my device
viewListArray = jsonArr.map((item) => {
console.warn(item.name);
});

jsonArray.forEach((item) => {
console.warn(item.name);
});
Array.forEach() will loop through an array.

on each second JSON object I don't have property name "name". and I did't check it. Now I'm checking like item.name == undefined?item.name:'';

Object.keys(data).forEach does not loop

I try to to get a value form json object.
var data={
"1":[{"departmentID":1,"departmentName":"Adminstration","branchId":1,"branchName":"ABC"}],
"2":[{"departmentID":2,"departmentName":"HR","branchId":2,"branchName":"DEF"}]
};
Object.keys(data).forEach(function(element, key, _array) {
console.log("branchId: "+element+" "+"BranchName : "+data[element][key].branchName)
for(dept of data[element]) {
console.log("Department name : "+dept.departmentName)
}
});
Here output is : the first result only and throws branchName is undefined exception.
But if the json object has multi object,its working fine.
var data={
"1":[{"departmentID":1,"departmentName":"Adminstration","branchId":1,"branchName":"ABC"}],
"2":[{"departmentID":2,"departmentName":"HR","branchId":2,"branchName":"XYZ"},
{"departmentID":3,"departmentName":"Food","branchId":2,"branchName":"XYZ"}]
}
I think, since I'm new to javascript, I couldn't solve. I tried a lot of reference to solve this problem, but I could not. Please try to solve this. Thanks in advance.

he first result only and throws branchName is undefined exception.
You need to replace
data[element][key].branchName
with
data[element][0].branchName
Because
element is the key "1",
so data[element] becomes [{"departmentID":1,"departmentName":"Adminstration","branchId":1,"branchName":"ABC"}],
data[element][0] becomes {"departmentID":1,"departmentName":"Adminstration","branchId":1,"branchName":"ABC"}
finally data[element][0].branchName is "ABC"

You have something mixed with your keys and indexes.
You can use Object.values (ES8 only) to get exact the values and left the keys part. Then iterate over them and make your strings.
const data = {
"1":[{"departmentID":1,"departmentName":"Adminstration","branchId":1,"branchName":"ABC"}],
"2":[{"departmentID":2,"departmentName":"HR","branchId":2,"branchName":"DEF"}]
}
Object.values(data).forEach(function(values) {
values.forEach(value => {
console.log(`branchId: ${value.branchId} BranchName: ${value.branchName} Department Name: ${value.departmentName}`);
});
});

Counting records in JSON array using javascript and Postman

I have a control that returns 2 records:
{
"value": [
{
"ID": 5,
"Pupil": 1900031265,
"Offer": false,
},
{
"ID": 8,
"Pupil": 1900035302,
"Offer": false,
"OfferDetail": ""
}
]
}
I need to test via Postman, that I have 2 records returned. I've tried various methods I've found here and elsewhere but with no luck. Using the code below fails to return the expected answer.
responseJson = JSON.parse(responseBody);
var list = responseBody.length;
tests["Expected number"] = list === undefined || list.length === 2;
At this point I'm not sure if it's the API I'm testing that's at fault or my coding - I've tried looping through the items returned but that's not working for me either. Could someone advise please - I'm new to javascript so am expecting there to be an obvious cause to my problem but I'm failing to see it. Many thanks.

In postman, under Tests section, do the following (screenshot below):
var body = JSON.parse(responseBody);
tests["Count: " + body.value.length] = true;
Here is what you should see (note: I replaced responseBody with JSON to mock up example above):

Correct your json. and try this.
=======================v
var test = JSON.parse('{"value": [{"ID": 5,"Pupil": 1900031265,"Offer": false},{"ID": 8,"Pupil": 1900035302,"Offer": false,"OfferDetail": ""}] }')
test.value.length; // 2
So you need to identify the array in the json (starting with the [ bracket. and then take the key and then check the length of the key.

Here's the simplest way I figured it out:
pm.expect(Object.keys(pm.response.json()).length).to.eql(18);
No need to customize any of that to your variables. Just copy, paste, and adjust "18" to whatever number you're expecting.

This is what I did for counting the recods
//parsing the Response body to a variable
responseJson = JSON.parse(responseBody);
//Finding the length of the Response Array
var list = responseJson.length;
console.log(list);
tests["Validate service retuns 70 records"] = list === 70;

More updated version of asserting only 2 objects in an array:
pm.test("Only 2 objects in array", function (){
pm.expect(pm.response.json().length).to.eql(2);
});

Your response body is an object you cannot find the length of an object try
var list = responseJson.value.length;

First of all you should convert response to json and find value path. Value is array. You should call to length function to get how many objects in there and check your expected size
pm.test("Validate value count", function () {
pm.expect(pm.response.json().value.length).to.eq(2);
});

I had a similar problem, what I used to test for a certain number of array members is:
responseJson = JSON.parse(responseBody);
tests["Response Body = []"] = responseJson.length === valueYouAreCheckingFor;
To check what values you're getting, print it and check the postman console.
console.log(responseJson.length);

Counting records in JSON array using javascript and insomnia
//response insomnia
const response = await insomnia.send();
//Parse Json
const body = JSON.parse(response.data);
//Print console:
console.log(body.data.records.length);

pm.test("Only 2 objects in array", function (){
var jsonData = pm.response.json();
let event_length = jsonData.data.length;
pm.expect(event_length).to.eql(2);
});

As mentioned in the comments, you should test responseJson.value.length
responseJson = JSON.parse(responseBody);
tests["Expected number"] = typeof responseJson === 'undefined' || responseJson.value.length;

I was facing similar issue while validating the length of an array inside a JSON. The below snippet should help you resolve it-
responseJson = JSON.parse(responseBody);
var list = responseBody.length;
tests["Expected number"] = responseJson.value.length === list;

Working Code
pm.test("Verify the number of records",function()
{
var response = JSON.parse(responseBody);
pm.expect(Object.keys(response.value).length).to.eql(5);
});
//Please change the value in to.eql function as per your requirement
//'value' is the JSON notation name for this example and can change as per your JSON

How do I find a JSON object using a nested expression?

From the example JSON below, I would like to return the target.id value of an object where the source.id == 'x'.
So where source.id == 'startId' return target.id == '3eecd840-e6a8-423c-a892-7df9646fde5d'.
{
"line":[
{
"type":"link",
"source":{
"id":"startId",
"port":"out"
},
"target":{
"id":"3eecd840-e6a8-423c-a892-7df9646fde5d",
"port":"in"
},
"id":"87d88a26-3a28-4db0-8016-71c1c4665f14"
},
{
"type":"link",
"source":{
"id":"3eecd840-e6a8-423c-a892-7df9646fde5d",
"port":"outYes"
},
"target":{
"id":"49940c02-70f2-4c53-ab50-9cbf96903600",
"port":"in"
},
"id":"9f8c365e-9ca7-440f-a722-c4f340782c0c"
}
]
}
I've tried JSONPath, but I cannot work out the expression to use. $.line[*].source.id gives me a list of source id's and $.line[?(#.source.id=='startId')] returns an error.
I also understand that I could iterate through each object in code, but It wouldn't be very efficient if I have tens or hundreds of 'lines' to work through. If possible I would like a more 'direct' path to the object.
I'm using javascript to code the rest of the app, so javascript examples would be helpful (with or without JSONPath).

If you're getting json as string, then use var json = JSON.parse(jsonStr). Then you can do it with Array.filter
var result = json.line.filter(function(obj){
return obj.source.id == "startId"
});
Then you could get the values like this
var ids = result.map(function(o){ return o.target.id });