Question

The examples in the Adobe Array doc are not very intuitive…

If I have a Card object with properties str and visible, how do I rewrite this piece of code looking for a visible card with the certain str value?

FOUND:
for each (var str:String in newHand) {
    for each (card in hand) {
        if (card.visible && str == card.str)
            continue FOUND;
    }

    // there is a new card - redraw the whole hand
    redrawHand(owner);
    break;
}

Answer 1

The some(), every() (and forEach()) methods of the Array class have two parameters:

• callback a function that is executed on each item, it should return true or false based on your criteria
• thisObject is an optional object you can supply to the callback function, inside the function you can refer to the object with the this keyword. You can form a closure with the callback function if you omit this parameter.

The signature of the callback function is as follows:

private var callback:Function = function(currentItem:Object, currentIndex:int, theEntireArray:Array):Boolean
{
    // your logic here returns true/false based on your critera
}

For your scenario, perhaps you could use the some() method like this:

private var comparisonString:String;

private function showTheExampleCode()
{
    for each (var str:String in newHand)
    {
        // comparisonString will be used in the closure
        // maybe you can just use str in the closure instead?
        comparisonString=str;
        if (hand.some(callback))
        {
            // at least one match was found, do something
        }
    } 
}

private var callback:Function(currentItem:Object, currentIndex:int, array:Array):Boolean
{
    // current item is a Card object (you probably do not have to cast it)
    return Card(currentItem).visible && Card(currentItem).str == comparisonString;
}