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<div id="pagetitle"><h1>YUI Library Examples: The YUI Global Object: Combine Data Sets with <code>merge</code></h1></div>
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<div id="bar-note"><p><strong>Note:</strong> This is YUI 3.x. Looking for <a href="http://developer.yahoo.com/yui/">YUI 2.x</a>?</p></div>
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<div class="yui-u first example" id="main">
<h2>The YUI Global Object: Combine Data Sets with <code>merge</code></h2>
<div id="example" class="promo">
<p>
<p><code>merge</code> allows you to combine any number of input objects and output a single merged set.<p>
<p>
If the input is a single object, the return value will be a shallow copy of the input, meaning that the return value
is a different object, but any non-primitive value in the input object is referenced in the returned
object.
</p>
<p>Click the "Merge" button to generate the merged set, the "Copy" button to create a shallow copy of an object.</p>
</p>
<div class="module example-container ">
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<p class="newWindowButton yui-skin-sam">
<a href="yui-merge_clean.html" target="_blank">View example in new window.</a>
</p>
</div> <div id="example-canvas" class="bd">
<!--BEGIN SOURCE CODE FOR EXAMPLE =============================== -->
<div id="demo">
<pre>set1 = { foo : "foo" };</pre>
<pre>set2 = { foo : "BAR", bar : "bar" };</pre>
<pre>set3 = { foo : "FOO", baz : "BAZ" };</pre>
<input type="button" name="demo_btn1" id="demo_btn1" value="Merge"/>
<input type="button" name="demo_btn2" id="demo_btn2" value="Copy"/>
<h3>result</h3>
<pre id="demo_result">click Merge or Copy</pre>
<script type="text/javascript">
YUI({base:"../../build/", timeout: 10000, filter:"debug", logInclude: {example:true}}).use("node", "dump",
// This method is in the core of the library, so we don't have to use() any
// additional modules to access it. However, this example requires 'node'
// and 'dump'.
function(Y) {
var set1 = { foo : "foo" };
var set2 = { foo : "BAR", bar : "bar" };
var set3 = { foo : "FOO", baz : "BAZ" };
var result = Y.get('#demo_result');
var doMerge = function () {
Y.log('set1 = ' + Y.dump(set1));
Y.log('set2 = ' + Y.dump(set2));
Y.log('set3 = ' + Y.dump(set3));
Y.log('Merging set1, set2, and set3');
var merged = Y.merge(set1, set2, set3);
Y.log('merged = ' + Y.dump(merged));
result.set('innerHTML', '<p>' + stringifyObj(merged) + '</p>');
};
Y.on('click', doMerge, '#demo_btn1');
var doCopy = function () {
// Create set4 with an object property 'obj'
var set4 = {
obj: {}
};
// Create a shallow copy of set4
var copy = Y.merge(set4);
// Add a property to the copy inside of the 'obj' property
copy.obj.addedToCopy = true;
Y.log('After modifying the copy: ');
// The result object is not the same as the original, but
var msg = ('"copy" should NOT be equal to the "original" (false expected): ' + (copy === set4));
// objects in the result object will reference the same object in
// the input object.
msg += '<br />copy.obj.addedToCopy should be equal to original.obj.addedToCopy (true expected): ' +
(copy.obj.addedToCopy === set4.obj.addedToCopy);
Y.log(msg);
result.set('innerHTML', '<p>' + msg + '</p>');
};
Y.on('click', doCopy, '#demo_btn2');
var stringifyObj = function (obj) {
var bits = ['{ '];
for (var k in obj) {
bits = bits.concat([k, ' : "', obj[k], '", ']);
}
bits[bits.length - 1] = '" }';
return bits.join('');
};
});
</script>
</div>
<!--END SOURCE CODE FOR EXAMPLE =============================== -->
</div>
</div>
</div>
<h2 class="first">Using <code>merge</code></h2>
<h3 class="first">Instantiate YUI</h3>
<textarea name="code" class="JScript">
<!-- include yui -->
<script type="text/javascript" src="../../build/yui/yui.js"></script>
YUI({base:"../../build/", timeout: 10000, filter:"debug", logInclude: {example:true}}).use("node", "dump",
// This method is in the core of the library, so we don't have to use() any
// additional modules to access it. However, this example requires 'node'.
function(Y) {
</textarea>
<h3>Merging hash tables</h3>
<p>When the "Merge" button is clicked, we merge three object literals in the form
of hash tables. Note the key values in later parameters override those in
previous parameters.</p>
<textarea name="code" class="JScript" cols="60" rows="1">
var set1 = { foo : "foo" };
var set2 = { foo : "BAR", bar : "bar" };
var set3 = { foo : "FOO", baz : "BAZ" };
var result = Y.get('#demo_result');
var doMerge = function () {
Y.log('set1 = ' + Y.dump(set1));
Y.log('set2 = ' + Y.dump(set2));
Y.log('set3 = ' + Y.dump(set3));
Y.log('Merging set1, set2, and set3');
var merged = Y.merge(set1, set2, set3);
Y.log('merged = ' + Y.dump(merged));
result.set('innerHTML', '<p>' + stringifyObj(merged) + '</p>');
};
Y.on('click', doMerge, '#demo_btn');
</textarea>
<h3>Creating Shallow Copies</h3>
<p>When the "Copy" button is clicked, we create use merge on a single
object in order to create a shallow clone. The code illustrates the
fact that object properties of the result object are shared with
the input object.</p>
<textarea name="code" class="JScript" cols="60" rows="1">
var doCopy = function () {
// Create set4 with an object property 'obj'
var set4 = {
obj: {}
};
// Create a shallow copy of set4
var copy = Y.merge(set4);
// Add a property to the copy inside of the 'obj' property
copy.obj.addedToCopy = true;
Y.log('After modifying the copy: ');
// The result object is not the same as the original, but
var msg = ('"copy" should NOT be equal to the "original" (false expected): ' + (copy === set4));
// objects in the result object will reference the same object in
// the input object.
msg += '<br />copy.obj.addedToCopy should be equal to original.obj.addedToCopy (true expected): ' +
(copy.obj.addedToCopy === set4.obj.addedToCopy);
Y.log(msg);
result.set('innerHTML', '<p>' + msg + '</p>');
};
</textarea>
<p>See the <code>clone</code> method to create deep copies of objects.</p>
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<h4>
The YUI Global Object Examples:</h4>
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<li><a href='../yui/yui-core.html'>YUI Core</a></li><li><a href='../yui/yui-more.html'>Load All Modules</a></li><li><a href='../yui/yui-multi.html'>Multiple Instances</a></li><li><a href='../yui/yui-compat.html'>YUI 2.x and 3.x</a></li><li><a href='../yui/yui-loader-ext.html'>YUI Loader - Dynamically Adding YUI and External Modules</a></li><li><a href='../yui/yui-extend.html'>Create Class Hierarchies with <code>extend</code></a></li><li><a href='../yui/yui-augment.html'>Compose Classes of Objects with <code>augment</code></a></li><li><a href='../yui/yui-mix.html'>Add Behaviors to Objects with <code>mix</code></a></li><li class='selected'><a href='../yui/yui-merge.html'>Combine Data Sets with <code>merge</code></a></li><li><a href='../yui/yui-isa.html'>Check Data Types with <code>Lang</code></a></li><li><a href='../yui/yui-ua.html'>Browser Detection with <code>UA</code></a></li> </ul>
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