Callback inside AJAX success

Question

Im trying to add an optional callback inside an AJAX successful execution, but I can't seem to get the callback to run when I want it to.

heres and example of my AJAX code

function someAjaxFunction(hosturl, callback){
    $.ajax({
        type: "GET",
        url: hosturl,
        data: {'something': 'code' },
        dataType: 'json',
        success: function(html){                       
            var arr = $.map(html, function(val) { return val; });
            if(arr[0] != 'false'){
                console.log('1');
                console.log('2');
                if (callback) {
                    console.log('calling the callback')
                    callback();
                }
                console.log('3');
            }else{
               console.log('fail') 
            }   
        }
    });
}

here is the callback and example of how the AJAX is being executed

function thisIsACallBack(){
    console.log("i'm a callback");
}

someAjaxFunction("some url", thisIsACallBack);

If I run this code the console outputs.

1
2
3
i'm a callback

I can even remove the callback if-condition all together and I would still get the same output.

Also is here a better way to handle my Ajax return currently my response wrapped inside a json object. If the database can't find the object I have to place 'false' inside an array and convert it to a json object before echoing it back to ajax.

Answer 1

Couse you have to pass your callback as string to your function

someAjaxFunction("some url", thisIsACallBack); // <-- Wrong thisIsACallBack will be triggered after someAjaxFunction as some separate function call

like this

someAjaxFunction("some url", "thisIsACallBack()"); // <- Correct way

// Then call eval( callback ); inside Ajax success
....
success: function(html){  
       ...
       eval( callback );
}

your problem was that in case of this code someAjaxFunction("some url", thisIsACallBack); it was triggering someAjaxFunction then thisIsACallBack function as you written someAjaxFunction name not as string

UPDATE

if you have to pass params to your callback your option is

someAjaxFunction("some url", function(param1){ 
    thisIsACallBack(param1) 
); } );

...
success: function(html){  
       ...
       callback( yourArray );
}

JavaScript has many ways how you can pass callbacks depends on your need