Singleton package addition, deletion, modification and check-JS Tutorial-php.cn

This time I will bring you the Singleton encapsulation of addition, deletion, modification and check. What are the precautions for the Singleton encapsulation of addition, deletion, modification and check? The following is a practical case, let’s take a look.

The example of this article describes how JS implements the function of encapsulating the addition, deletion, modification and checking of data based on thesingleton mode(Singleton) in thedesign pattern. Share it with everyone for your reference, the details are as follows:

Single-case mode

The core structure of the single-case mode only contains one called A special class of singletons. The singleton pattern can ensure that a class in the system has only one instance.

The original definition of the singleton pattern appeared in "Design Patterns" (Addison Wesley, 1994): "Guarantee that a class has only one instance. And provide a global access point to access it. "

Singleton pattern definition: "A class has one and only one instance, and it is instantiated and provided to the entire system.”

var Singleton = (function(){ SingletonClass() { } var singleton = null; return { getInstance: function() { if (singleton == null) { singleton = new singletonClass(); } else { return singleton; } } } })(); Singleton.getIntance();

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The front end often uses some asynchronous operations related to interfaces such as addition, deletion, modification and query. Let's take an example. When I operate a data list, I often add the modify and delete functions. Some solutions use synchronous (refresh the page), and the user experience is better using asynchronous;

The code is as follows

Add function

$(".add").click(function(){ $.ajax({ type: "post" dataType:"json", url: "http://www.jb51.net/", data: {name:"csdn博客",dir:"web前端"}, success: function( result ){ if ( result.status ) { alert("新增成功！") } else { alert("新增失败") } }, error: function(){ alert("新增出现异步，请得新增加或联系技术管理员"); } }); });

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Delete function

$(".del").click(function(){ $.ajax({ type: "post" dataType:"json", url: "http://www.jb51.net/", data: {id:"1"}, success: function( result ){ if ( result.status ) { alert("删除成功！") } else { alert("删除失败") } }, error: function(){ alert("新增出现异步，请得新增加或联系技术管理员"); } }); });

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The above two code snippets briefly describe the JS code for adding and deleting functions. Some students discovered that they have something in common, that is, part of the ajax requests are the same, and what if the delete function is also used in other places? , then you need to write the same code in other places. I feel very uncomfortable

Let’s improve it

var SingletonCRUD = (function(){ SingletonClass() {} SingletonClass.prototype = { constructor: SingletonClass, add: function( data ) { $.ajax({ type: "post" dataType:"json", url: "http://www.jb51.net/", data: data, success: function( result ){ if ( result.status ) { alert("新增成功！") } else { alert("新增失败") } }, error: function(){ alert("新增出现异步，请得新增加或联系技术管理员"); } }); }， remove: function( data ) { $.ajax({ type: "post" dataType:"json", url: "http://www.jb51.net/", data: data, success: function( result ){ if ( result.status ) { alert("删除成功！") } else { alert("删除失败") } }, error: function(){ alert("新增出现异步，请得新增加或联系技术管理员"); } }); } } var singleton = null; return { getInstance: function() { if (singleton == null) { singleton = new singletonClass(); } else { return singleton; } } } })(); var curd = SingletonCRUD.getIntance(); $(".add").click(function(){ var data = {"name":"name"}; curd.add( data ); }); $(".del").click(function(){ var data = {"id": 1}; curd.remove( data ); });

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I often use Singleton instances to make some Tool tool classes;

The advantages of using design patterns: decoupling, strong readability, The code structure is clear;

Through the above small example, the acquisition data (click event function) and operation data (ajax request) in the click event are separated;

Through the singleton mode The optimized code:

var SingletonCRUD = (function(){ SingletonClass() {} SingletonClass.prototype = { constructor: SingletonClass, ajax: function(url, data success ){ $.ajax({ type: "post" dataType:"json", url: url, data: data, success: success, error: function(){ alert("新增出现异步，请得新增加或联系技术管理员"); } }); }, add: function( data ) { this.ajax("http://www.jb51.net/", data, function( result ){ if ( result.status ) { alert("新增成功！") } else { alert("新增失败") } }); }， remove: function( data ) { this.ajax("http://www.jb51.net/", data, function( result ){ if ( result.status ) { alert("删除成功！") } else { alert("删除失败") } }); } } var singleton = null; return { getInstance: function() { if (singleton == null) { singleton = new singletonClass(); } else { return singleton; } } } })();

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The ajax method in SingleClass is also equivalent to a facade mode (Facade), hiding internal details and exposing an interface to the outside;

I believe you have read the case in this article You have mastered the method. For more exciting information, please pay attention to other related articles on the php Chinese website!