How to encapsulate plug-ins in jquery

In web development, jquery is a very popular Javascript library. jQuery has a rich plug-in ecosystem, because it provides a convenient plug-in encapsulation method, allowing us to encapsulate reused code into plug-ins for easy reuse in projects.

This article will introduce the encapsulation method of jquery plug-in to help you write efficient code quickly.

1. Basic structure of plug-in

A jquery plug-in contains the following parts:

1.Plug-in name
2.Default parameters
3.Plug-in Main function
4.Extension method
5.Instance object

We will introduce these parts one by one below.

1. Plug-in name

The plug-in name is important, it should be descriptive and clear and easy to understand. We should avoid using names that are too concise or too general. For example: "myPlugin" or "pluginLibrary1" don't provide much information. A good plug-in name can help others better understand our plug-in.

2.Default parameters

Our plug-in should have default parameters to allow users to use the plug-in when no parameters are specified. Default parameters should be thoroughly defined to avoid any unnecessary guesswork.

3. Plug-in main function

This is where the core function of the plug-in is located. Inside the function we will complete all the required code. This function should have one parameter, which is an object property used to pass user-defined parameters and configuration information. The following is a sample code:

(function($){

$.fn.myPlugin = function(options){
   var settings = $.extend({
        //在这里定义默认参数
    }, options);        
   //插件主体函数
}    

}(jQuery));

The first line of code is a self-running anonymous function. The parameter is jQuery. The parameter $ is quoted to ensure that the $ alias is available inside the plugin. The plug-in function is mounted on jQuery.fn, turning it into a jQuery plug-in.

$.fn.myPlugin is the name of the plug-in, and options is the configuration object we pass to the plug-in.

4. Extension method

The extension method means that we can extend the plug-in into more functions. We can add more methods to the plugin. They should be as objects inside the new function since they have different functions.

Sometimes, we also use internal methods, so there is no need to expose them as independent methods. These methods are not used by other plugins.

For example:

(function($){

$.fn.myPlugin = function(options){
    var settings = $.extend({
        //默认配置项
    }, options);
    var methods = {
      init: function(){},
      verify: function(){},
      processData: function(){}
    };
    //插件主体函数
    function mainFunc(){
        methods.init();
        methods.verify();
        methods.processData();
    }
    return this.each(function(){
        mainFunc();
    });
};

}(jQuery));

In the above example, we use inside the plugin Object "methods" to define the "init", "verify" and "processData" methods.

5. Instance object

Finally, we need to create an instance object for the plug-in. This is achieved using jquery $.data(). The $.data() method allows us to attach data to an element so that our plugin can be used on it. Here is an example:

(function($){

$.fn.myPlugin = function(options){
   var settings = $.extend({
        //默认配置项
    }, options);
    var methods = {
        //插件方法 
    };        
    //插件主体函数
    function main(){
        //核心功能代码
    }       
    return this.each(function(){
        //获取jQuery对象
        var $this = $(this);
        
        //检测我们的插件是否已经应用
        var data = $this.data('myPlugin');
        
        //如果插件未被初始化，则初始化插件
        if(!data){
            $this.data('myPlugin', {
                target: $this,
                methods: methods
            });
            main();
        }
    });
};

}(jQuery));

In this example, we first use the jQuery object to get the current element. We then check to see if the element already contains our plugin information, and if not, add that information to the element's data -- the data name is myPlugin.

The above is the basic structure. Next, we'll show you how to define some common functionality to extend your plugin.

2. Extend plug-in functions

When using jQuery to write plug-ins, we can add various functions to extend plug-in functions. Here are a few examples to help you understand:

1. Add styles

You can add styles to your plugin by using CSS stylesheets. You can place these styles in the color configuration options of your plugin. As shown below:

$.fn.myPlugin = function(options){

var settings = $.extend({
    color: '#ffffff'
}, options);

return this.each(function(){
    $(this).css('color', settings.color);
});

}

In the above example, we add the user specified color to the element in the style attributes.

2. Event handling

You can also add event handling functions to respond to your plug-in behavior. For example, you can add a mouse click event like this:

$.fn.myPlugin = function(options){

var settings = $.extend({
   onClick: function(){}
}, options);

return this.each(function(){
    $(this).click(function(event){
        event.preventDefault();
        settings.onClick.call(this, event);
    });
});

};

In the above example , we first create a default onClick function and then merge it with the user's configuration. Then we bind the click event to each element. When the event is fired, we call the configured onClick function and fire it on the current element.

3. Implementing chained calls

jQuery is often called the Javascript library for chained calls because it allows you to chain all DOM operations together. This feature can also be applied to your plugins to provide a chained API to use your plugins.

For example, we can add a setOption method to our plug-in, and then enable it to implement chain calls. As shown below:

$.fn.myPlugin = function(options){

var settings = $.extend({
   onClick: function(){},
   option: null
}, options);

var methods = {
    setOption: function(option){
        return this.each(function(){
            $(this).data('option', option);
        });
    }
}

return this.each(function(){
    //实现链式调用
    var $this = $(this).data('myPlugin',{'methods': methods});
    $this.data('option', settings.option);
    
    $this.click(function(event){
        event.preventDefault();
        settings.onClick.call(this, event, $this.data('option'));
    });
});

};

In the above example, we added the setOption function in the method, Then the chain call is implemented through it. In the code below, we show how to use chained calls to set options:

$("#my-element").myPlugin().myPlugin('setOption', {

option: 'myOption'

});

In the above example, the myPlugin() method is first called, which will create a myPlugin object. Then call the setOption method through this object, passing the options object to it. In this way, we implement chain calls.

4. 对外公开API

我们可以使用 jQuery.fn.extend() 方法扩展对外公开的API。这样就可以在很多不同的方法中重用代码。下面是一个示例：

$.fn.myPlugin = function(){

var methods = {
    method1: function(){
        console.log('method1');
        return this;
    },
    method2: function(){
        console.log('method2');
        return this;
    }
};
this.method1 = methods.method1;
this.method2 = methods.method2;
return this;

};

在上面示例中，我们使用this关键字将每个方法都添加到了插件函数上。这意味着每次我们调用myPlugin()方法时，我们都可以直接调用这些方法。

我们可以通过使用如下代码来调用这个函数：

$("#my-element").myPlugin().method1().method2();

以上是本文的内容，希望通过这些例子能够帮助您更好地理解jQuery插件封装，从而开发更高效的插件。

The above is the detailed content of How to encapsulate plug-ins in jquery. For more information, please follow other related articles on the PHP Chinese website!