Question

I have a problem with Javascript Literal functions.

    for (curitem in array)
    {
        var tl = new GTileLayer(copyrightCollection, 0, 21 );

        tl.getTileUrl = function(a, b)  { 
                return MyFunction(a, b, curitem); 
            };

        ...

        secondArray.push(tl);
    } 

The problem is: When “MyFunction” is called, the third parameter has always the last value used in function creation (values are like 0,1,2,3,4,6 and I always receive 6).

How can I solve this?

Thank you

Answer 1

Classic problem with loops and closures. You can easily solve it by creating a new variable every loop, e.g. by using an anonymous function and passing the value as a parameter:

for (var curitem in array) {
    var tl = new GTileLayer(copyrightCollection, 0, 21);

    (function(curitem) {
        tl.getTileUrl = function(a, b) { 
            return MyFunction(a, b, currentitem); 
        };
    })(curitem);

    // ...

    secondArray.push(tl);
}