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Extracting a data from json array by certain key in java script

I have a json array which im getting my react data from it,
the json is like this:
{
"Folders": [
{
"name": "parent 2",
"children": [ //this is children_1
{
"name": "parent 2",
"id": "parent 2",
"children": [] //this is children_2
}
],
"id": 1
}
]
}
lets say i have the key value of name inside children(children_1) and i want to get the rest of the data inside that children using the name that i have, is there a way to do that ?

Look at jsonpath
so it will be
var json = require('jsonpath');
var names = jp.query(json, '$.Folders[*].children[*].children');

Taking contents of an array of objects, and assigning them to a property on a JSON object

I want to take items from this array (the way I save things on the client)
[
{
"id": "-Mdawqllf_-BaW63gMMM",
"text": "Finish the backend[1]",
"status": true,
"time": 1625248047800
},
{
"id": "-Mdawqllf_-BaW63gGHf",
"text": "Finish the middle-end[2]",
"status": false,
"time": 1625248040000
},
{
"id": "-Mdawqllf_-BaW63gGHd",
"text": "Finish the front-end[3]",
"status": false,
"time": 1625248040000
}
]
And turn them into this format for how I save it server side
{ "todos": {
"-Mdawqllf_-BaW63gMMM": {
"text": "Finish the backend[1]",
"status": true,
"time": 1625248047800,
},
"-Mdawqllf_-BaW63gGHf": {
"text": "Finish the middle-end[2]",
"status": false,
"time": 1625248040000,
},
"-Mdawqllf_-BaW63gGHd": {
"text": "Finish the front-end[3]",
"status": false,
"time": 1625248040000,
}
},
}
Basically i turn items into an array on the client to help with sorting and making use of arrays. But before sending it back need to put into the right format

Use .map() to loop over the array of objects to exctract the id property, so you can use it as the key of the new object.
Use Object.fromEntries() to create the new object from the array returned by .map().
const data = [
{
"id": "-Mdawqllf_-BaW63gMMM",
"text": "Finish the backend[1]",
"status": true,
"time": 1625248047800
},
{
"id": "-Mdawqllf_-BaW63gGHf",
"text": "Finish the middle-end[2]",
"status": false,
"time": 1625248040000
},
{
"id": "-Mdawqllf_-BaW63gGHd",
"text": "Finish the front-end[3]",
"status": false,
"time": 1625248040000
}
];
const todos = {
Todos: Object.fromEntries(data.map(obj => [obj.id, obj]))
};
console.log(todos);

#Barmar's solutions is nice.
For the sake of learning or others googling. You can also reduce the array to an object.
const todos = data.reduce((obj, item) => {
obj[item.id] = item
return obj
}, {})

const items = {
todos: {
...data
}
};
Assume that data is the array of objects.
Use the spread operator to copy all the array objects from data array to the todos object at key todos.
One important thing to note that you can't assign more than one objects without array to a single object key. You definately have to use the array to maintain all the objects under the one key.
Avoid using the hardcode index. Always use the spread operator

How to get JSON entry from returned objects

I got JSON data, like:
{
"id": 1,
"active": true,
"dependency": [
{ "id": 2 }
{ "id": 3 }
]
},
{
"id": 2,
"active": true
},
{
"id": 3,
"active": true
}
I want to retrieve the "active" value for each dependency in the id 1 object. So far I used a forEach to get those dependency.
thisElement.dependency.forEach(function(id) {
console.log(id)
}
Which returns id 2 and id 3 as objects. Is there a way to use id.active straight away? By using only one loop? Because the result so far are objects without any connection to the related JSON data. Would it require to loop through the whole JSON data to retrieve those values?

The most efficient thing to to is create a hashmap with an Object or Map first so you only need to iterate the array once to find dependency related values.
You could do it by using Array#find() to search whole array each time but that is far more time complexity than the o(1) object lookup
const activeMap = new Map(data.map(obj => [obj.id, obj.active]))
data[0].dependency.forEach(({id}) => console.log(id ,' active: ' , activeMap.get(id)))
<script>
const data =
[
{
"id": 1,
"active": true,
"dependency": [
{"id": 2 },
{"id": 3}
]
},
{
"id": 2,
"active": false
},
{
"id": 3,
"active": true
}
]
</script>

check json object exist to be save into localstorage

[
{
"id": 1,
"title": "my Item",
"body": ""
},
{
"id": 2,
"title": "my Item 2",
"body": ""
},
{
"id": 3,
"title": "my Item 3",
"body": ""
}
]
Is above json structure good for storing says users viewed books? I have other key like users' setting so I try to nested/group things to be neater. My question is how can I check an object with value exist or not so I won't insert duplicated data. How to check the id 2 is existed in this case? Do I have to loop?

Do I have to loop?
Yes you have to loop ( or use a method which will do it) :
var idToCheck="id";
var valToCheck=2;
var a = your array...
var wasFound=false;
a.forEach(function(entry) {
if (entry[idToCheck]==valToCheck)
{
wasFound=true;
return;
}
});
//do whatever with `wasFound`.
http://jsbin.com/jigefamiqu/1/edit

Delete object from json tree by reference in JavaScript

I need to remove an object from an JSON tree. I know a reference to that object. Is there a nice way to do it via JavaScript or jQuery besides traversing the whole tree?
Example:
party = {
"uuid": "4D326531-3C67-4CD2-95F4-D1708CE6C7A8",
"link": {
"rel": "self",
"href": "http://localhost:8080/cim/party/4D326531-3C67-4CD2-95F4-D1708CE6C7A8"
},
"type": "PERSON",
"name": "John Doe",
"properties": {
"CONTACT": [
{
"category": "CONTACT",
"type": "EMAIL",
"key": "email",
"value": "john.doe#doe.at",
"id": "27DDFF6E-5235-46BF-A349-67BEC92D6DAD"
},
{
"category": "CONTACT",
"type": "PHONE",
"key": "mobile",
"value": "+43 999 999990 3999",
"id": "6FDAA4C6-9340-4F11-9118-F0BC514B0D77"
}
],
"CLIENT_DATA": [
{
"category": "CLIENT_DATA",
"type": "TYPE",
"key": "client_type",
"value": "private",
"id": "65697515-43A0-4D80-AE90-F13F347A6E68"
}
]
},
"links": []
}
And i have a reference: contact = party.properties.contact[1]. And I want to do something like delete contact.

You may delete it this way. I just tested it.
var party = {
// ...
}
alert(party.properties.CONTACT[0]) // object Object
delete party.properties.CONTACT[0] // true
alert(party.properties.CONTACT[0]) // undefined
Fiddle
UPDATE
In the case above party is a direct property of window object
window.hasOwnProperty('party'); // true
and that's why you can't delete a property by reference. Anyhow, behavior of delete operator with host objects is unpredictable. Though, you may create a scope around the party object and then you'll be allowed to delete it.
var _scope = {};
var _scope.party = {
// ...
};
var r = _scope.party.properties.CONTACT[0];
window.hasOwnProperty('party'); // false
alert(r) // object Object
delete r // true
alert(r) // undefined

It only works one way: a variable holds a reference, but there is no way given a particular reference to infer what variables hold it (without iterating over them and comparing).