Develop Reference

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

JSON list optimization

I want to create a JSON API that returns a list of objects. Each object has an id, a name and some other information. API is consumed using JavaScript.
The natural options for my JSON output seems to be:
"myList": [
{
"id": 1,
"name": "object1",
"details": {}
},
{
"id": 2,
"name": "object2",
"details": {}
},
{
"id": 3,
"name": "object3",
"details": {}
},
]
Now let's imagine that I use my API to get all the objects but want to first do something with id2 then something else with id1 and id3.
Then I may be interested to be able to directly get the object for a specific id:
"myList": {
"1": {
"name": "object1",
"details": {}
},
"2": {
"name": "object2",
"details": {}
},
"3": {
"name": "object3",
"details": {}
},
}
This second option may be less natural when somewhere else in the code I want to simply loop through all the elements.
Is there a good practice for these use cases when the API is used for both looping through all elements and sometime using specific elements only (without doing a dedicated call for each element)?

In your example you've changed the ID value from 1 to id1. This would make operating on the data a bit annoying, because you have to add and remove id all the time.
If you didn't do that, and you were relying on the sorted order of the object, you may be in for a surprise, depending on JS engine:
var source = JSON.stringify({z: "first", a: "second", 0: "third"});
var parsed = JSON.parse(source);
console.log(Object.keys(parsed));
// ["0", "z", "a"]
My experience is to work with arrays on the transport layer and index the data (i.e. convert array to map) when required.

Indexing array values in an object in an IndexedDB

For a Chrome app, wich stores data in IndexedDB, i have a object like this:
var simplifiedOrderObject = {
"ordernumber": "123-12345-234",
"name": "Mr. Sample",
"address": "Foostreet 12, 12345 Bar York",
"orderitems": [
{
"item": "brush",
"price": "2.00"
},
{
"item": "phone",
"price": "30.90"
}
],
"parcels": [
{
"service": "DHL",
"track": "12345"
},
{
"service": "UPS",
"track": "3254231514"
}
]
}
If i store the hole object in an objectStore, can i use an index for "track", which can be contained multiple times in each order object?
Or is it needed or possibly better/faster to split each object into multiple objectStores like know from relational DBs:
order
orderitem
parcel
The solution should also work in a fast way with 100.000 or more objects stored.

Answering my own question: I have made some tests now. It looks like it is not possible to do this with that object in only 1 objectStore.
An other example object which would work:
var myObject = {
"ordernumber": "123-12345-234",
"name": "Mr. Sample",
"shipping": {"method": "letter",
"company": "Deutsche Post AG" }
}
Creating an index will be done by:
objectStore.createIndex(objectIndexName, objectKeypath, optionalObjectParameters);
With setting objectKeypath it is possible to address a value in the main object like "name":
objectStore.createIndex("name", "name", {unique: false});
It would also be possible to address a value form a subobject of an object like "shipping.method":
objectStore.createIndex("shipping", "shipping.method", {unique: false});
BUT it is not possible to address values like the ones of "track", which are contained in objects, stored in an array. Even something like "parcels[0].track" to get the first value as index does not work.
Anyhow, it would be possible to index all simple elements of an array (but not objects).
So the following more simple structure would allow to create an index entry for each parcelnumber in the array "trackingNumbers":
var simplifiedOrderObject = {
"ordernumber": "123-12345-234",
"name": "Mr. Sample",
"address": "Foostreet 12, 12345 Bar York",
"orderitems": [
{
"item": "brush",
"price": "2.00"
},
{
"item": "phone",
"price": "30.90"
}
],
"trackingNumbers": ["12345", "3254231514"]
}
when creating the index with multiEntry set to true:
objectStore.createIndex("tracking", "trackingNumbers", {unique: false, multiEntry: true});
Anyhow, the missing of the possibility to index object values in arrays, makes using indexedDB really unneeded complicated. It's a failure in design. This forces the developer to do things like in relational DBs, while lacking all the possibilities of SQL. Really bad :(

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).

How to sort an array of objects in ascending order of number?

I have an array of objects like the following :
var array = {
"112" : {
"id": "3",
"name": "raj"
},
"334" : {
"id": "2",
"name": "john"
},
"222" : {
"id": "5",
"name": "kelvin"
}
}
Now i want to sort the array in ascending order of id and then restore it in array. I tried using sort() but could not do it. Please help how to do so that when i display the data from the array it comes sorted.

Assuming you meant your code to be an array of objects, ie:
var unsortedArray = [
{ id: 3, name: "raj" },
{ id: 2, name: "john" },
{ id: 5, name: "kelvin" }
];
Then you would be able to sort by id by passing a function to Array.sort() that compares id's:
var sortedArray = unsortedArray.sort(function(a, b) {
return a.id - b.id
});
As others have pointed out, what you have is an object containing objects, not an array.

var array = {
"112" : {
"id": "3",
"name": "raj"
},
"334" : {
"id": "2",
"name": "john"
},
"222" : {
"id": "5",
"name": "kelvin"
}
}
var sortedObject = Array.prototype.sort.apply(array);
result:
{
"112": {
"id": "3",
"name": "raj"
},
"222": {
"id": "5",
"name": "kelvin"
},
"334": {
"id": "2",
"name": "john"
}
}

That isn't an array, it is an object (or would it if it wasn't for the syntax errors (= should be :)). It doesn't have an order.
You could use an array instead (making the current property names a value of a key on the subobjects).
Alternatively, you could use a for loop to build an array of the key names, then sort that and use it as a basis for accessing the object in order.

JavaScript objects are unordered by definition. The language specification doesn't even guarantee that, if you iterate over the properties of an object twice in succession, they'll come out in the same order the second time.
If you need things to be ordered, use an array and the Array.prototype.sort method.

That is an object but you can sort an array ilke this:
Working Demo: http://jsfiddle.net/BF8LV/2/
Hope this help,
code
function sortAscending(data_A, data_B)
{
return (data_A - data_B);
}
var array =[ 9, 10, 21, 46, 19, 11]
array.sort(sortAscending)
alert(array);​

Not many people knows that Array.sort can be used on other kinds of objects, but they must have a length property:
array.length = 334;
Array.prototype.sort.call(array, function(a, b) {return a.id - b.id;});
Unfortunately, this doesn't work well if your "array" is full of "holes" like yours.