Directly store object properties in array of objects, without creating full object in javascript

Question

var cartArray = [];
//in a loop
    var cartObject = {};
    cartObject.item_name = 'NAME';
    cartObject.quantity = number;
    cartObject.amount =  number;
    cartObject.total = cart.amount * cart.quantity;
    cartObject.subtotal = cart.subtotal + cart.total;
    // store
cartArray[i]=cartObject;

can we directly store like on the fly without having full information of cartObject

var cartArray=[]
cartArray[i].item_name ='NAME'
cartArray[i].quantity =number

this thing works like

var cartArray=[]
cartArray[i]={}// it needs to be defined for each i
cartArray[i].item_name ='NAME'
cartArray[i].quantity =number

can we bypass this thing

Why not use cartArray[i] = {item_name: 'NAME', quantity: number, …};? — Bergi
– Bergi, Commented Jul 22, 2020 at 15:04
I don't have all the information of object, and I want to store in property if required. Like at some point I want to have added new property like "discount" in array index n. to store new property — Prateek Raj Gautam
– Prateek Raj Gautam, Commented Jul 22, 2020 at 15:16
Yes, you can add properties to an object at any time. But the object must already exist in the array for a cartArray[i].discount = number assignment to succeed. If you did create the objects in the first loop, and then afterwards add a new .discount property to them, it will work just fine. Did you try it? — Bergi
– Bergi, Commented Jul 22, 2020 at 15:18
(I would however recommend that you create the objects with all their properties initially, and keep their values undefined until the point where you get the information). — Bergi
– Bergi, Commented Jul 22, 2020 at 15:20

8HoLoN · Accepted Answer · 2020-07-22 15:11:42Z

1

Here is what you want:

var cartArray = [];
//in a loop
cartArray[i] = {
    item_name: 'NAME',
    quantity: number,
    amount: number,
    total: cart.amount * cart.quantity,
    subtotal = cart.subtotal + cart.total
}

answered Jul 22, 2020 at 15:11

8HoLoN

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Bergi · Accepted Answer · 2020-07-22 15:31:47Z

1

I want to update G[2].mobileVar=1233 but I don't know if I have defined the object already

In that case, you can write

if (!G[2]) G[2] = {};
G[2].mobileVar = 1233;

to create the object only if it does not already exist in the array.

answered Jul 22, 2020 at 15:31

Bergi

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