Accessing Object's Data Via Another Variable Name

Question

It's super late and my mind is blanking right now, but let's say I have variable filename and it's storing the name of another variable marker. The variable marker is an array and contains the object & property position: new google.maps.LatLng(42.2550,-114.3221).

I've been stupidly trying to access it via filename.position which of course returns undefined, since it's searching the literal filename for a 'position' property that does not exist.

But how could I pull marker.position by using filename? Is there some nifty jQuery trick for, uh, 'resolving' a variable to its contents? I'm brain fried. I know I've done this before.

Use bracket notation: window[filename].postion, for instance. — apsillers
– apsillers, Commented May 14, 2013 at 12:35
@apsillers It will work only in case if filename was defined globally. — VisioN
– VisioN, Commented May 14, 2013 at 12:35
@VisioN Yes, that's exactly why I said "for instance" -- it's an example of how bracket notation could be used to access a property of window. Certainly, a complete answer would explain the larger context of how to avoid globals (e.g., object namespacing), but the syntax would be identical. — apsillers
– apsillers, Commented May 14, 2013 at 12:36

Devtrix.net · Accepted Answer · 2013-05-14 13:02:57Z

2

If it's possible in your script, you can store the data not just in variable, but in a property of some object (usually it's more convenient to use global one). For example

var myObj = {};
myObj.marker = new google.maps.LatLng(42.2550,-114.3221); // or anything else

Then you will be able to get this property using a variable like this:

myObj[filename].position

In this case i would also recomment to check for myObj[filename] existance using typeof structure, just to make sure such property exists in myObj.

if (typeof myObj[filename] !== "undefined") {
  // do something
}

As apsillers noted, you could use global window object for this as well. But if your marker variable was defined inside some other function (i.e. not global), you won't be able to access it with window.marker or window[filename] as it will be out of scope.

Second way is to use eval() function which i'd strongly recommend to avoid.

answered May 14, 2013 at 13:02

Devtrix.net

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1 Comment

daveycroqet Over a year ago

Unfortunately, my variable was local inside another function. I then wanted to access it inside a separate jQuery function, so I had to go global with window. If I had the foresight, none of that would have been necessary. Not sure how to reconcile it without using globals and I'm unwilling to do a total rewrite for the nonce. Regardless, thanks anyway!

Ankit Tyagi · Accepted Answer · 2013-05-14 13:07:44Z

0

Try this :

window[filename].position;

answered May 14, 2013 at 13:07

Ankit Tyagi

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