I've just started working at a new company and noticed something that looks completely wrong to me in a lot of their JS. I'm a bit hesitant to bring it up without confirming this is wrong since I'm pretty junior, I'm not a JS expert and it's only my second day and I don't want to look stupid.
So, normally I'd expect the module pattern to look something like:
MODULENAME = MODULENAME || {};
MODULENAME.SUBMODULENAME = (function() {
var bla = {};
bla.somefunction = function() {
//do stuff
};
//add more stuff to bla
return bla;
}());
What they have all over their code is:
MODULENAME = MODULENAME || {};
MODULENAME.SUBMODULENAME = (function() {
var that = this;
that.somefunction = function() {
//do stuff
};
//add more stuff to that
return that;
}());
Now of course because the function isn't being called as a constructor with the new
keyword or as a method, this
is bound to window
and they're defining that
as this
. So they're basically dumping everything in the global object and all their sub-module names are in fact aliases for window
. Is there any reason anyone would want to do this? Or is this really as wrong as it seems to me?
Edit:
I made a mistake in putting var
before the submodule definition, originally I wrote something slightly different and forgot to delete the var
. I've tried to make the example a bit clearer too, hopefully it's more obvious what I mean now.
Edit 2:
Also I've looked at the scripts executing in Firebug and they are definitely adding everything to window
, that object is a total mess.
Yes it looks wrong.
MODULENAME = MODULENAME || {}; // missing var
var MODULENAME.SUBMODULENAME = (function() { // probably the missing var from above...
var that = this;
//add some stuff to that
return that; // that is the WINDOW- wrong.
}());
DEMO for the damage it can do:
var x = function() {
alert('out');
}
var MODULENAME = MODULENAME || {};
MODULENAME.SUBMODULENAME = (function() {
var that = this;
that.x = function() {
alert('DAMAGE');
}
}());
x(); // alert DAMAGE and not "out" - messed up with the global object!
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