What Does '(function($) {})(jQuery);' Really Do?

Question:

Can someone clarify the purpose and variations of the following jQuery plugin syntaxes?

<br>(function($) {})(jQuery);<br>

How does it differ from these examples:

Type 1:

<br>(function($) {</p>
<pre class="brush:php;toolbar:false">$.fn.jPluginName = {

    },

    $.fn.jPluginName.defaults = {

    }

})(jQuery);

Type 2:

<br>(function($) {</p>
<pre class="brush:php;toolbar:false">$.jPluginName = {

    }

})(jQuery);

Type 3:

<br>(function($){</p>
<pre class="brush:php;toolbar:false">//Attach this new method to jQuery
$.fn.extend({ 

    var defaults = {  
    }  

    var options =  $.extend(defaults, options);  

    //This is where you write your plugin's name
    pluginname: function() {

        //Iterate over the current set of matched elements
        return this.each(function() {

            //code to be inserted here

        });
    }
}); 

})(jQuery);

Answer:

Breaking Down '(function($) {})(jQuery);'

This code snippet is commonly used to define a closure that immediately calls the enclosed function, passing jQuery as an argument. It's equivalent to:

<br>function($) {}($);<br>

This technique is employed to create a local scope for the plugin, preventing conflicts with other plugins or global variables.

Plugin Syntax Variations:

Type 1:

This syntax attaches methods and default options to $.fn, effectively creating a jQuery plugin that can be accessed as $(element).jPluginName().

Type 2:

This syntax extends the jQuery core functionality rather than creating a plugin. It's useful for adding traversal functions or other utilities to jQuery itself.

Type 3:

This syntax is similar to Type 1 but uses $.fn.extend to attach the plugin method to the jQuery prototype. It provides a structured and modular way to create plugins.

Which Syntax to Use:

Type 1 should be used to create plugins that manipulate DOM elements.
Type 2 should be used when extending jQuery core functionality.
Type 3 is the preferred choice for most plugin development scenarios.

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