How to include reference to original function when doing an override with jQuery.extend()

Question

So, I'm trying to override a function but include it's original methods with the jQuery.extend() method.

    var origFunction = $.fn.pluginFunction;
    $.fn.extend({
        pluginFunction: function() {
               // `origFunction` is available via Closure, 
               // now how can I declare the $.extended function here
               // to preserve the original methods and then override
               // only the following object?

                   myObject = {
                        'key1' : 'val1',
                        'key2' : 'val2',
                   }
        }
    });

score 2 · Answer 1 · answered Oct 04 '12 at 17:44

2

Use apply() to call the original.

origFunction.apply(this,arguments);

but if myObject is a local variable inside of origFunction, it is not going to make a difference.

answered Oct 04 '12 at 17:44

epascarello

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This doesn't work because executing `origFunction.apply(this,arguments)` executes the function prematurely . I'm trying to debug it, and add a callback so that I can ensure the function is properly extended before executing it but the `origFunction()` apply that you suggested is actually the source of my problem - walking through it in debugger, it is at this line where the plugin executes prior to being extended. – Brian Oct 04 '12 at 20:15
How does it execute it prematurely? Not getting what you mean. – epascarello Oct 04 '12 at 20:35

Anoop · Answer 2 · 2012-10-04T17:51:07.093

2

Modified code: call origFunction using apply. You change myObject only if it is not a private variable of method(it should be global accessible from overriding method).

var origFunction = $.fn.pluginFunction;
    $.fn.extend({
        pluginFunction: function() {
               origFunction.apply(this, arguments); // 
               // `origFunction` is available via Closure, 
               // now how can I declare the $.extended function here
               // to preserve the original methods and then override
               // only the following object?

                   myObject = {
                        'key1' : 'val1',
                        'key2' : 'val2',
                   }
        }
    });

edited Oct 04 '12 at 17:51

answered Oct 04 '12 at 17:45

Anoop

23,044
10
62
76

This doesn't work because executing `origFunction.apply(this,arguments)` executes the function prematurely . I'm trying to debug it, and add a callback so that I can ensure the function is properly extended before executing it but the `origFunction()` apply that you suggested is actually the source of my problem - walking through it in debugger, it is at this line where the plugin executes prior to being extended. – Brian Oct 04 '12 at 20:17

score 0 · Answer 3 · answered Oct 04 '12 at 17:59

User apply()

apply calls a function with a set of arguments. It's not part of jQuery, it's part of core Javascript. However, there is mention of it in the jQuery docs:

http://docs.jquery.com/Types#Context.2C_Call_and_Apply

Syntax:

somefunction.apply(thisobj, argsarray)

The above calls the function somefunction, setting this to thisobj within the function's scope, and passing in the arguments from argsarray as the arguments to the function.

How to include reference to original function when doing an override with jQuery.extend()

3 Answers3