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How to create json array of object if the key already exist

I'm a beginner with JavaScript and query. I have an html form where the user can add or remove a group of fields. The group of fields contains 1 select and 3 inputs. The group of fields added have the same name of the previouses and so on.
What I'm trying to do is retrieve the value creating a structure like this.
{
"colture1": [{
"code_app": "A2",
"long": "1",
"lat": "103"
}, {
"code_app": "B34",
"long": "11",
"lat": "12"
}],
"colture2": [{
"code_app": "GH3456",
"long": "55",
"lat": "90"
}]
// ....and so on
}
If the user selects a colture that already exist in the object, I'd like to add the others value in the same key as you can see in "colture1". My problem is here, I can't create an array where I can add the others value, now my function override the preovious values, It writes the last one values and it doesn't create an array.
This is my function
$('#create_json').on("click", function(e) {
const json_data = {};
var cat = "";
for (const input of document.querySelectorAll(".card[mainBlock] select, .card[mainBlock] input")) {
if (input.tagName === 'SELECT') {
cat = input.value;
} else {
(json_data[cat] = json_data[cat] || {})[input.name] = input.value;
}
}
console.log(JSON.stringify(json_data));
})
Here I can put a demo here https://jsfiddle.net/ou7h4f2m/3/. Thank you in advance

It is probably easier if you would deal with one section in each outer loop iteration (just on .card[mainBlock]), and then use an inner loop for processing the category and properties:
$('#create_json').on("click", function (e) {
const data = {};
for (const section of document.querySelectorAll(".card[mainBlock]")) {
const cat = section.querySelector("select").value;
const obj = Object.assign(...Array.from(section.querySelectorAll("input"), input =>
({ [input.name]: input.value })
));
(data[cat] = data[cat] || []).push(obj);
}
console.log(JSON.stringify(data));
});
I would not call your main variable json_data. It does not represent JSON, but a JavaScript object. JSON is what you get from calling JSON.stringify.

Find index of filtered array

I have a JSON object which looks like this:
var JSON = {
"implants":[{
"familyId": "3",
"reference": "1234",
"quantity": "3"
},{
"familyId": "2",
"reference": "3456",
"quantity": "1"
}]
}
I'm building a function which searches whether an implant with the given "reference" is already in the array. If it's not, it just gets added to the array. Easy. If it is in the array, then I want to add the new quantity to the existing quantity and then update the array.
function returnTheseImplantsWhere(key1,key2){
return function(el){
if(el[key1]==key2) {
return el;
}
}
}
var activeCaseImplants = JSON.parse(getLocal("activeCaseImplants"));
var existingImplant = activeCaseImplants.implants.filter(returnTheseImplantsWhere("reference", window.currentImplantRef));
if(existingImplant.length) {
//previously added implant
newImplantQty = Number(existingImplant[0].quantity) + Number($("#qty").val());
existingImplant.quantity = newImplantQty;
} else {
//new implant
}
My question relates to the "previously added implant" section of the above code (which all works as expected). I now have the updated quantity, but I can I determine which object within the activeCaseImplants.implants array needs it's quantity updated? I feel like I could make use of indexOf somewhere around the line beginning with var existingImplant = ... but I'm not sure where or how. Any ideas?

Extract objects from object in JSON using JavaScript

So, I have access to a JSON-file and I'm supposed to list a few items in a neat fashion. The JSON-file is however written in a way I'm not familiar with. I have the following code:
function readFile(file) {
var rawFile = new XMLHttpRequest();
rawFile.open("GET", file, false);
rawFile.onreadystatechange = function ()
{
if (rawFile.readyState === 4 && rawFile.status === 200)
{
window.openedFile = JSON.parse(rawFile.responseText);
console.log(JSON.stringify(openedFile, undefined, 4));
createList();
}
};
rawFile.send();
}
function createList() {
var table = document.createElement('table');
var body = document.createElement('tbody');
for (var i = 0; i < openedFile.sites.length; i++) {
var item = document.createElement('tr');
var colSite = document.createElement('td');
colSite.appendChild(document.createTextNode(openedFile.sites[i].name));
item.appendChild(colSite);
body.appendChild(item);
}
table.appendChild(body);
document.getElementById('list').appendChild(table);
}
..and it does not work as it claims the array "sites" is empty. The result from the JSON-file in the output in the console gives (with slight modifications in the variable names):
{
"sites": {
"1007": {
"id": 1007,
"name": "Location B",
"devices": {
"p3": {
"name": "p3",
"version": "5"
}
}
},
"1337": {
"id": 1337,
"name": "Location A",
"devices": {
"p2": {
"name": "p2",
"version": "5"
},
"p1": {
"name": "p1",
"version": "5"
}
}
}
},
}
If I change the JSON-file and add [] brackets after sites and remove "1007" and "1337" it looks like I'm used to (as an ordinary array), and it works. I'm pretty sure I'm not allowed to do this however and I get the same problem again when trying to extract information about the devices. I would appreciate any help on this matter. And to clarify, I'm trying to avoid changing the JSON-file, if there is some other solution.

The numerals 1007 and 1337 are properties of the object sites. Use a for-in loop to iterate through the object properties.
var sites = openedFile.sites;
for(var site in sites){
console.log("Key: ", site);
console.log("Value: ", sites[site]);
}

Sites is an object, not an array, so you need to iterate over the object's properties, not the elements of the array.
In order to get a list of those properties, you can use Object.keys(). That gives you an array of the property names.
Once you have that array, you iterate over it and each time use the current element, which is the name of the property of the original object.
For example, this works (just console logging the object name, the extraction you've already got):
function createList2() {
var len = Object.keys(openedFile.sites); //get array of property keys
for (var i of len) { //iterate over the array of property keys
console.log(openedFile.sites[i].name); /*retrieve properties by key from original object */
}
}

Access Data from Ajax Call Jquery

I am using Jquery Ui Autocomplete.
The problem I have is the data that is being returned from my api.
"{"d":{"results":[],"facets":{"facet_counts":{"Town":{"":0,"londonderry":136914,"london bridge":1,"london":8983316,"london colney":1}}},"__solr_time":3473457,"__ser_time":1564,"__t_time":1421,"__count":9120232,"__max_score":1.0}}"
I have run it through an online parser and it is valid, but I don't know how to access the list of towns with the corresponding number next to it.
Any help would be appreciated

I was able to access the Town "name" and number using:
var test = {
"d": {
"results": [],
"facets": {
"facet_counts": {
"Town": {
"": 0,
"londonderry": 136914,
"london bridge": 1,
"london": 8983316,
"london colney": 1
}
}
},
"__solr_time": 3473457,
"__ser_time": 1564,
"__t_time": 1421,
"__count": 9120232,
"__max_score": 1
}
}
for(var prop in test.d.facets.facet_counts.Town){
console.log(prop);
console.log(test.d.facets.facet_counts.Town[prop]);
}

Just run JSON.parse() on the string and then pull out the Town node.
var string; // the data string returned by API.
var dataObj = JSON.parse(string);
var Town = dataObj.d.facets.facet_counts.Town;
// access the properties as needed
var londonCount = Town.london;
var londonBridgeCount = Town['london bridge']; // need to use bracket notation to get this one

Use a JSON array with objects with javascript

I have a function that will get a JSON array with objects. In the function I will be able to loop through the array, access a property and use that property. Like this:
Variable that I will pass to the function will look like this:
[{
"id": 28,
"Title": "Sweden"
}, {
"id": 56,
"Title": "USA"
}, {
"id": 89,
"Title": "England"
}]
function test(myJSON) {
// maybe parse my the JSON variable?
// and then I want to loop through it and access my IDs and my titles
}
Any suggestions how I can solve it?

This isn't a single JSON object. You have an array of JSON objects. You need to loop over array first and then access each object. Maybe the following kickoff example is helpful:
var arrayOfObjects = [{
"id": 28,
"Title": "Sweden"
}, {
"id": 56,
"Title": "USA"
}, {
"id": 89,
"Title": "England"
}];
for (var i = 0; i < arrayOfObjects.length; i++) {
var object = arrayOfObjects[i];
for (var property in object) {
alert('item ' + i + ': ' + property + '=' + object[property]);
}
// If property names are known beforehand, you can also just do e.g.
// alert(object.id + ',' + object.Title);
}
If the array of JSON objects is actually passed in as a plain vanilla string, then you would indeed need eval() here.
var string = '[{"id":28,"Title":"Sweden"}, {"id":56,"Title":"USA"}, {"id":89,"Title":"England"}]';
var arrayOfObjects = eval(string);
// ...
To learn more about JSON, check MDN web docs: Working with JSON
.

This is your dataArray:
[
{
"id":28,
"Title":"Sweden"
},
{
"id":56,
"Title":"USA"
},
{
"id":89,
"Title":"England"
}
]
Then parseJson can be used:
$(jQuery.parseJSON(JSON.stringify(dataArray))).each(function() {
var ID = this.id;
var TITLE = this.Title;
});

By 'JSON array containing objects' I guess you mean a string containing JSON?
If so you can use the safe var myArray = JSON.parse(myJSON) method (either native or included using JSON2), or the usafe var myArray = eval("(" + myJSON + ")"). eval should normally be avoided, but if you are certain that the content is safe, then there is no problem.
After that you just iterate over the array as normal.
for (var i = 0; i < myArray.length; i++) {
alert(myArray[i].Title);
}

Your question feels a little incomplete, but I think what you're looking for is a way of making your JSON accessible to your code:
if you have the JSON string as above then you'd just need to do this
var jsonObj = eval('[{"id":28,"Title":"Sweden"}, {"id":56,"Title":"USA"}, {"id":89,"Title":"England"}]');
then you can access these vars with something like jsonObj[0].id etc
Let me know if that's not what you were getting at and I'll try to help.
M

#Swapnil Godambe
It works for me if JSON.stringfy is removed.
That is:
$(jQuery.parseJSON(dataArray)).each(function() {
var ID = this.id;
var TITLE = this.Title;
});

var datas = [{"id":28,"Title":"Sweden"}, {"id":56,"Title":"USA"}, {"id":89,"Title":"England"}];
document.writeln("<table border = '1' width = 100 >");
document.writeln("<tr><td>No Id</td><td>Title</td></tr>");
for(var i=0;i<datas.length;i++){
document.writeln("<tr><td>"+datas[i].id+"</td><td>"+datas[i].Title+"</td></tr>");
}
document.writeln("</table>");