Dynamically Add Variable Name Value Pairs to JSON Object

Mike picture Mike · Nov 1, 2010 · Viewed 299k times · Source

I have a json object full of ips like

var ips = {}

I then add ip objects to this object like so

ips[ipID] = {}

I then need to add dynamic/variable name value pairs to each ip so I am using code like this

var name; var value; var temp = {};
tmp[name] = value

My question is, how can I add these name value pairs/ tmp to my ipID objects so that my outcome turns out like

ipID = { name : value, anotherName : anotherValue }

Answer

Guffa picture Guffa · Nov 1, 2010

That's not JSON. It's just Javascript objects, and has nothing at all to do with JSON.

You can use brackets to set the properties dynamically. Example:

var obj = {};
obj['name'] = value;
obj['anotherName'] = anotherValue;

This gives exactly the same as creating the object with an object literal like this:

var obj = { name : value, anotherName : anotherValue };

If you have already added the object to the ips collection, you use one pair of brackets to access the object in the collection, and another pair to access the propery in the object:

ips[ipId] = {};
ips[ipId]['name'] = value;
ips[ipId]['anotherName'] = anotherValue;

Notice similarity with the code above, but that you are just using ips[ipId] instead of obj.

You can also get a reference to the object back from the collection, and use that to access the object while it remains in the collection:

ips[ipId] = {};
var obj = ips[ipId];
obj['name'] = value;
obj['anotherName'] = anotherValue;

You can use string variables to specify the names of the properties:

var name = 'name';
obj[name] = value;
name = 'anotherName';
obj[name] = anotherValue;

It's value of the variable (the string) that identifies the property, so while you use obj[name] for both properties in the code above, it's the string in the variable at the moment that you access it that determines what property will be accessed.