CODEWITHSUNDEEP
javascriptjquery
Rod Johnson
Rod Johnson

Reputation: 2427

How does JavaScript deal with function objects? See example

I have a function like this

function saveProfile(data, url, successFn) {

    $.ajax({

        dataType: 'json',
        data: data,
        url: url,
        type: 'post',
        success: function () {
            successFn();
        }
    });
}

is there any difference to passing the successFn directly like this...

function saveProfile(data, url, successFn) {

    $.ajax({

        dataType: 'json',
        data: data,
        url: url,
        type: 'post',
        success: successFn
    });
}

Upvotes: 1

Views: 147

Answers (4)

PleaseStand
PleaseStand

Reputation: 32082

The difference is that in the first example, successFn will not get the callback function arguments. Neither will the this object be the same; in fact, it will be window rather than whatever may be specified as the context for the .ajax() call if the function is not a member of an object (in xyz.successFn(), this would be xyz).

The first approach is less concise and possibly slower; by "wrapping" the function, you are quite possibly using more browser memory and CPU time. I wouldn't use the first approach unless you are paid by the line of code or you need this to point to an object that successFn is a member of.

Upvotes: 3

mikerobi
mikerobi

Reputation: 20878

The first version would let you perform some additional operations, before or after you execute successFn, but as it is currently written, there is no benefit, and the second version is much cleaner.

Also, this doesn't have anything to do with function objects.

Upvotes: 0

Chris Tonkinson
Chris Tonkinson

Reputation: 14459

If the only thing you want to do on success is call successFn(), then no, there isn't any practical difference between the two methods you describe. That said, I'd go with the latter since it's cleaner and quicker.

Upvotes: 2

automagic
automagic

Reputation: 1077

To be clear, in the first example, you are wrapping the function successFn in another anonymous function, so you are in effect calling 2 functions. The second example, as others have stated, passes the function itself, and is correct for what you are doing.

Upvotes: 0

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