Wordpress jQuery functions

Question

I am pulling my hair out over this one. I have functions defined in separate files both loaded with wp_enqueue_scripts. In each file I wrap the functions between

(function($){

})(jQuery);

The problem is when I try to call one function that is defined in a different file I get "The function xxxx is not defined" I verified that the scripts are loaded in the correct order and that there are no errors. I can call the function within the same file and it works alright but when I try to call it from a different file it doesn't. Is there some sort of "Namespace" or something that I am missing?

EDIT: I understand what is going on... When I declare a function inside the (function($)... it is not in the global scope. If I define the function outside of it I can access it. So my question is how do I define a function in the global scope from within the (function($)..?

EDIT 2: OK I got something working. I found out if I declare the function like:

ShowForm = function(url){
   ...
}

instead of

function ShowForm(url){
   ...
}

it works. Can anyone explain to me why I have to declare the function this way? Is there an alternative way to define the function so it is available in the global scope?

it seems at first case, you had to look at namespace anyway. — Banzay
– Banzay, Commented Dec 13, 2014 at 20:22

David · Accepted Answer · 2014-12-14 01:16:08Z

1

1st off your jquery code invokes a anonymous function so we are dealing with a functions scope and it runs immediately as encountered.

(function(){.....} ) //anonymous function syntax

Any functions you create within a function will not be available outside the function. But here we are incorrectly referring to functions...it should actually be "function Object" rather than functions and in js you can assign objects to variables.

MyNewFunction = (function() {......}); // function object now assigned to variable MyNewFunction

So in your 2nd example this is what you are doing.

Within function objects, you can create global variables (i.e. you are not reusing a global variable already created). If you use the keyword var before the variable, the variable will be local in scope.

aVariable = 'im global'; //global scope

(function() {
    MyVar= 'im global and can be called outside this function';
    var MyOtherVar= 'im not global and cannot be called outside this function';
    aVariable = 'change this';
});

console.log(MyVar); // global scope = 'im global and can be called outside this function'
console.log(MyOtherVar); // local to above function only scope = undefined
console.log(aVariable); // = global scope (unchanged scope) = 'change this'

Hence when you create a global variable within a function and assign a function object to it, the function object is now available after the function creating it has been called (at parse time in this case)

(function() {
    MyVar= function() {'alert function running'};
});

MyVar(); // works creates alert

Theres nothing wrong with setting functions this way, but if they are intended for use without modification (i.e. the function doesn't change dependant on something else) you would improve readability of the code for yourself by declaring functions in the global scope in the first place.

answered Dec 14, 2014 at 1:16

David

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2 Comments

Andy Braham Over a year ago

Thanks David, is there a better way of declaring the functions global other than assigning them to a variable?

David Over a year ago

all function objects are technically assigned to a var (sort of) function foo() is used with foo , foo= function can be used with foo() also. But as prev. mentioned its much more readable to define functions outside of other functions. Any variables can be controlled inside the expressions anyway.

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