JQuery verify if a var is a function

Question

How i verify if my callBackFunction is defined as a function with jquery?

var callBackFunction =window['columnActive'];
(...)
            "fnRowCallback": function (nRow, aData, iDisplayIndex, iDisplayIndexFull) {
                if ($.isFunction(callBackFunction)) {
                    alert('cheguei');
                    columnActive(nRow, aData, iDisplayIndex, iDisplayIndexFull);
                }

        }

Ignore the top answer in the duplicate, [this](http://stackoverflow.com/a/6000009/519413) is the correct answer — Rory McCrossan, Jul 06 '16 at 15:50

ssube · Accepted Answer · 2016-07-06T15:50:13.037

3

You don't need jQuery for this, the built-in (and globally supported) typeof operator will tell you:

if (typeof callBackFunction === 'function')

typeof also works even if callBackFunction was never defined or declared, while jQuery and others will throw an error if you call $.isFunction(x) and x was never declared.

edited Jul 06 '16 at 15:50

answered Jul 06 '16 at 15:45

ssube

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still fail on the test – Fabio Santos Jul 06 '16 at 15:52
Then maybe `callBackFunction` *isn't* a function... – ssube Jul 06 '16 at 15:52
to declare a var is a function is this way:var callBackFunction = window['columnActive']; correct? – Fabio Santos Jul 06 '16 at 15:58
I think the problem is how I declare the var callBackFunction – Fabio Santos Jul 06 '16 at 17:59
I figure out, its because is in document ready – Fabio Santos Jul 06 '16 at 18:30

JQuery verify if a var is a function

1 Answers1