<link href="{{componentAssets}}/node.css" rel="stylesheet" type="text/css">
<div class="intro">
    <p>This example demonstrates how to use multiple NodeList features to build a simple game.</p>
</div>

<div class="example">
{{>ducks-source}}
</div>


<h2>The HTML</h2>
```
{{>ducks-html}}
```

<h2>YUI Instance</h2>
<p>
The `use` statement doesn't include `node` because it's loaded as a requirement of transition.
</p>
```
YUI().use('transition', 'button', function(Y){
    // code goes here
});
```

<h2>Setting Vars</h2>
<p>
The variable `ducks` is used for easily manipulating all the ducks at once.
We'll display various duck comments from the array `squawkTextArr` on a rotating basis. 
</p>
```
    var ducks = Y.all('.duck-row li'),
        ducksRemaining = 10, // value for UI display
        squawkTextIndex = 0, // index in the squawkTextArr to use next
        squawkTextArr = [   // duck comments
            '#@&~*Q!',
            'Hey!?',
            '911 on U!',
            "U&nbsp;fly's&nbsp;down",
            'duck&nbsp;pile!',
            'Ricochets&nbsp;kill!',
            'how&nbsp;sporting.',
            "shoe's&nbsp;untied"
        ];
```

<h2>Initializing the Ducks</h2>
<p>
Repetitive markup is added with the `.append()` method to all the ducks in the `NodeList`.
This keeps the original markup simple and clear.
</p>
```
    // append the same content for each duck <li>
    ducks.append('<img src="../assets/node/images/duck.png"/><div class="squawk"><div class="text">#@&~*Q!</div><div class="small-squawk-bubble"></div></div>');
```
<p>
All the ducks in the `NodeList` are given the `set-up` class with the `.addClass()` method.
This class is found on any duck that has the state of being set up, as opposed to being knocked down.
</p>
```    
    // give them all the set-up state class
    ducks.addClass('set-up');
```
<p>
This state could be a Boolean property, but it's handy as a class, 
because a `NodeList` can be made containing the squawks of all "set up" ducks in this way, 
`squawks = Y.all('.duck-row .set-up .squawk');` 
as we'll see in the `makeDucksSquawk` function.
</p>

<h2>Making the Ducks Swim</h2>
<p>
This uses `transition` to make the ducks swim right to left 
</p>
```
    // this makes the ducks move from right to left.
    // When the duck on the far left disappears from view,
    // it's added to the far right end of the row.
    var makeDucksSwim = function () {
        var frontDuck;
        
        // move the duck row to the left one duck space over 2 seconds
        Y.one('.duck-row').transition({
            easing: 'linear',
            left: '-119px',
            duration: 2
        }, function () { // when the row finishes its right to left transition...
            // remove the first duck on the left
            // which has trasitioned out of view
            frontDuck = Y.one('.duck-row li').remove();

            // append the removed first duck onto the right end
            Y.one('.duck-row').appendChild(frontDuck);

            // set the position for the next makeDucksSwim()
            Y.one('.duck-row').setStyle('left', '10px');

            // if there are ducks remaining, make them swim again
            if (ducksRemaining > 0) {
                makeDucksSwim();
            }
        });       
    }
    makeDucksSwim(); // this initializes the ducks swimming
```

<h2>Click Event Handler</h2>
<p>
</p>
```
    // handles a click on a duck
    var duckClick = function(e) {
        var squawks;
        
        // remove the squawk belonging to the duck that was clicked
        e.currentTarget.one('.squawk').setStyles({'top': '-400px', 'opacity': '1'});
        
        // makes the ducks appear to lay back when clicked
        e.target.transition({
            duration: 0.2,
            height: '3px',
            width: '133px'
        });
        
        // the clicked duck will no longer have the 'set-up' class/state
        e.currentTarget.removeClass('set-up');
        makeDucksSquawk(); // makes the ducks squawk
        updateDucksRemaining(); // update the number of ducks still set up
    };
```

<h2>Squawking Ducks</h2>
<p>
</p>
```
    // this makes the duck's squawks show and hide and get various text
    var makeDucksSquawk = function(){    
        squawks = Y.all('.duck-row .set-up .squawk'); // a NodeList of the squawks of set-up ducks
        if (Y.one('#show-attitude')._node.checked) {  // only have ducks squawk if the checkbox is checked
            // fill voice bubbles with next text string
            Y.all('.duck-row .set-up .squawk .text').setHTML(squawkTextArr[squawkTextIndex]);
            
            // increment the index to get the next squawk text
            squawkTextIndex = (squawkTextIndex += 1) % (squawkTextArr.length);
            squawks.transition({
                top: {
                    delay: 0.5,
                    value: '0px', // drop squawks into position from hidden 
                    duration: 0   // instant position change
                },
                opacity: { // fade out
                    delay: 3.0,
                    duration: 0.3,
                    value: 0
                } 
            }, function(e){
                // after squawks are faded out,
                // move them to hidden position and set opacity to 1 again
                squawks.setStyles({'top': '-400px', 'opacity': '1'});
            });
        }
    }
```

<h2>Reset and Ducks Remaining</h2>
```
    // This resets all ducks, "ducks remaining" counters, and row position
    // make the duck images full height
    // start them swimming     
    var reset = function() {
        Y.all('.duck-row li img').setStyle('height', '55px');
        Y.all('.duck-row li').addClass('set-up');
        updateDucksRemaining();
        makeDucksSwim();
    }
    
    // counts the ducks remaining, and updates the UI counter display
    var updateDucksRemaining = function() {
        ducksRemaining = Y.all('.gallery li.set-up').size();    
        Y.one('.ducks-remain').setHTML(ducksRemaining);    
    }
```
<h2>Prefer `node.delegate()` over `nodelist.on()`</h2>

<p>Sometimes you need to create individual subscriptions for each Node in a 
NodeList, but usually it's preferable to use 
<a href="node-evt-delegation.html">event delegation</a> as shown in this example.</p>

<h2>Listeners</h2>
<p>

</p>
```
    // listeners
    Y.one('.duck-row').delegate('click', duckClick, 'li');
    Y.one('#button-reset').on('click', reset);
```

<h2>Complete Ducks Example Source</h2>
```
{{>ducks-source}}
```