rgbflawed rgbflawed - 4 months ago 30
Javascript Question

What is Facebook's function __d

I'm working on a project that (hopefully) involves taking advantage of some of the javascript that's already built into Facebook. But right away I've got a roadblock in that I can't figure out what

__d
is.

If you look at the source javascript files, pretty much every command begins with
__d


For example:

__d("legacy:live-timer",["LiveTimer"],function(a,b,c,d){a.LiveTimer=b('LiveTimer');},3);


But I can't find anywhere in any of the javascript files what
__d
actually does. Shouldn't it have to be defined somewhere for all these other functions to take advantage of it?

UPDATE:

So let's say there's a site with some javascript like this...

function alertSomething(var) {
if (var) alert("Here it is: "+var);
}

if (some condition) alertSomething("something");


Now let's say I had a Chrome Extension and I was able to inject my own Javascript into the page. Couldn't \my Chrome Extension Javascript have something like this...

if (some other condition) alertSomething("something else");


Thus I would be taking advantage of some code that exists in the javascript already on the page?

Answer

I found the definition of __d on line 20 of 1LWPxIBQ4v0.js. No idea if the file is named the same for everyone. Search for "a.__d=function(s,t,u,v)" (a is the global object, i.e. window, effectively making __d a global function). Good luck with that de-minification though...