set json property depending on child property

Question

I am creating this JSON object

 {
    "attachment": {
        "type": "template",
        "payload": {
            "template_type": "generic",
            "image_aspect_ratio": "square"
            "elements": [
                new CreateBallon(results[rand])
            ]
        }
    }
}

I want to set the image_aspect_ratio in only if elements[0].someProp is present. How can I do that?

write a conditional statement: `"image_aspect_ratio": myObj.attachment.payload.elements[0] === someProp ? square : ''` — JJJ, Nov 19 '17 at 02:38
can I write `this.attachment.payload` instead of `myObj.attachment.payload` because i am reffering to current object ? — Parteek Dheri, Nov 19 '17 at 02:40
You cannot refer to `this` until the object is fully constructed — Muhammad Usman, Nov 19 '17 at 02:48
so I can first create and save the JSON object, then check if that property exists, then I can edit it again to set `image_aspect_ratio` right?? — Parteek Dheri, Nov 19 '17 at 02:51
yup. Just set `image_aspect_ratio = ""` when creating object and change its value after that if your condition is true — Muhammad Usman, Nov 19 '17 at 02:54
[There's no such thing as a "JSON Object"](https://stackoverflow.com/questions/2904131/what-is-the-difference-between-json-and-object-literal-notation) — charlietfl, Nov 19 '17 at 02:54
@ParteekDheri let me know if you be able to do that successfully — Muhammad Usman, Nov 19 '17 at 02:57

score 1 · Accepted Answer · answered Nov 19 '17 at 03:06

Let's clear what JSON is. It is a textual notation for data. If you do anything with the object that involves code of Javascript don't call it JSON so, The object you're talking about is not a JSON but a JavaScript object created via object literal notation.

Now to answer your query, you can't refer to this object before you've fully initialized that object. So what you can do is initialize your object with some default value and then you should be able to edit any property based on the properties from the same object. Something like

 var obj = {"property1" : "X", "property2" : ""};

Now you can update your object like

  obj.property2 = obj.property1 =='yourCondition' ? 'NewValue' : obj.property2

set json property depending on child property

1 Answers1