Unsure why variable is undefined. Possible scope issue?

Question

If you look at the function below, on line 11 where it alert(template);. It prints undefined. If I alert(template); inside the ajax succes

Answer 1

ajax is asynchronous. to explain in simple terms: ajax works like it runs on a separate "thread", processing in the background while your code continues.

by the time you called load_template(), it alerts after $.ajax() was called but before the template was returned thus undefined.

what you can do is this so everything runs after a success has been returned:

function load_template(path, data, callback){

    $.ajax({
        url: path,
        success: function(uncompiled_template){
            var template = Handlebars.compile(uncompiled_template);

            alert(template);    

            if(callback){
                callback(template, data);
            }else{
                return template(data);
            }
        }
    });
}