Adding item to a json object

Question

I saw many questions in Stackoverflow but i didn't find what exactly responds to my query.

I need to add an element to my json object:

var JSONObject = {
 "shape0": {
 "id": "id0",
 "x1": 0,
 "x2": 0,
 "y1": 0,
 "y2": 0
 },
 "shape1": {
 "id": "id1",
 "x1": 2,
 "x2": 2,
 "y1": 2,
 "y2": 2
 }
};

I used this syntax but in vain:

var newShape = "shape2";
JSONObject.newShape.id = "id2";

NOTE: The first thing, is that a json object? Any help will be appreciated

• user1807367: this uses arrays not json object, isn't it?
• Brian Roach: Java has nothing to do with Javascript. Tag removed.
• Dave Lawrence: What you are doing makes no sense.
• Joe: This is not a JSON object. It's a JavaScript object.
• user1807367: @Joe : could you plz give me the right JSON object

Answer 1

Assuming you want to build a similar structure as the rest:

JSONObject.shape2 = {
 id: 'id2',
 "x1": 4,
 "x2": 4,
 "y1": 4,
 "y2": 8
};

Or:

var shapeName = 'shape2';
JSONObject[shapeName] = {
 ...
};

Btw, these are not JSON objects; they are just objects, in JavaScript.

Update

The following wouldn't work:

var newShape = "shape2";
JSONObject.newShape.id = "id2";

First of all, the notation is wrong; you need to use [newShape]. But that's not the main reason; it doesn't work because you can't dereference an object that doesn't exist yet.

JSONObject[newShape]

This will be undefined, so this:

JSONObject[newShape].id

Will result in an error TypeError: Cannot set property 'id' of undefined

• user1807367: i want to make it json object, how?
• Brian Roach: +1 for the correct answer. Sadly, I don't think it's going to help.
• Pinoniq: JSON stands for Javascript Object Notation meaning you are writing plain Javascript. JSON === javascript object
• Ja͢ck: @Pinoniq Not sure if you're agreeing with me or not; but yeah, JSON is just a notation; it's not plain JavaScript though, because keys must be quoted in JSON.
• Ja͢ck: @abualbara It's an object, just like what you have.

Answer 2

You need:

var newShape="shape2";
JSONObject[newShape].id = "blar"; 

• user1807367: then, i can use that: JSONObject.shape2.id ?