Copying AJAX JSON object into existing Object

Question

I have several Javascript prototypes. Initially, instances will have only ID's filled in, with some generic place holder information for other data. I then send a message to the server with the ID and the object type (using jQuery's AJAX function) and the server returns a JSON object with all the missing information (but no ID). The variables in the returned object have the exact same name as those in the existing object.

What's the easiest way to transfer this into the existing empty object? I've come up with a few alternatives

set the object equal to the returned object, then copy in the id (loses prototype functions?)
create a function for each object that takes an object with identical structure and copies the data
loop through the key-value pairs of the JSON object to and copy them to existing object

If I use the third option, is this the correct way to do that? :

for (var key in json) {
    if (object.hasOwnProperty(key)) {
        object[key] = json[key];
    }
}

assuming json is the returned object and object is the existing object.

If json is plain JSON then I don't think you even need the hasOwnProperty check. Unless someone has been funking with Object.prototype. — Paul Grime
– Paul Grime, Commented May 4, 2013 at 10:48
The question is, what do you want to do with your JSON-Object. If you want to evaluate to an object, JSON.parse() does the trick for you. If you want to merge it to an existing object, jQuery.extend() would be a better suggestion. — Thomas Junk
– Thomas Junk, Commented May 4, 2013 at 11:15
@PaulGrime I'm doing that as a precaution in case there's an extra key in the json object that I don't want in the existing object. If you'll notice, I'm looping through keys in json but checking against object. — Jaws212
– Jaws212, Commented May 4, 2013 at 17:53

Karthik Sankar · Accepted Answer · 2020-01-08 15:58:28Z

19

Alternative without jQuery is to use the javascript Object.assign method.

Object.assign(targetObject, json);

answered Jan 8, 2020 at 15:58

Karthik Sankar

9168 silver badges11 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

palaѕн · Accepted Answer · 2013-05-04 10:50:24Z

13

Try this using extend():

var newObject = jQuery.extend({}, oldObject);

answered May 4, 2013 at 10:50

palaѕн

74.2k17 gold badges123 silver badges140 bronze badges

1 Comment

Jaws212 Over a year ago

Sounds perfect! I wasn't aware of this functionality at all. And because it merges all properties, any inheritance I have done will still stick, correct?

HMR · Accepted Answer · 2013-05-04 10:48:52Z

1

You can use jQuery.extend: http://api.jquery.com/jQuery.extend/

$.extend(object1,object2);

If your JSON is a string then create an object from that first:

var object1=$.parseJSON(myJsonString);

answered May 4, 2013 at 10:48

HMR

39.5k26 gold badges99 silver badges175 bronze badges

3 Comments

Thomas Junk Over a year ago

There is no need for a Methodcall parseJSON(), hence nowadays everybody could use JSON.parse(). jQuery does nothing else: if (window.JSON && window.JSON.parse) { return window.JSON.parse(data); }

HMR Over a year ago

but if window.JSON.parse is false it'll do a bit more.

vvondra Over a year ago

but window.JSON.parse will not fail today

Collectives™ on Stack Overflow

Copying AJAX JSON object into existing Object

3 Answers 3

Comments

1 Comment

3 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

3 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related