JavaScript plug-in development tutorial (2)_javascript skills

1, opening analysis

Hi, everyone! Do you still remember the previous article------the beginning of this series (JavaScript plug-in development tutorial 1). It mainly talks about "how to develop plug-ins using jQuery",

So today we will continue our plug-in development journey with yesterday’s questions. Previous questions are as follows:

(1) If the project technology selection changes and these plug-ins are strongly dependent on the "jQuery" mechanism, the plug-ins we wrote before will not be able to be used (assuming that jQuery is not used). How to refactor?

(2), Refactor the key logic of the plug-in, how will we organize it?

Okay, let’s study today’s article with questions.

First of all, I am not denying the "jQuery plug-in method". Secondly, we need to analyze the problem from different angles. For example, "jQuery plug-in has the following advantages":

(1), put all the code in a closure (an immediate execution function). At this time, the closure is equivalent to a private scope, the internal information cannot be accessed by the outside, and there will be no pollution of global variables.

(2), a) avoid global dependencies; b) avoid third-party damage; c) compatible with jQuery operators '$' and 'jQuery '.

Then how will we organize the code when refactoring? Is it object-oriented thinking (OOP)? Or should we follow the process-based approach to the end? Or is it a combination of the two? Hahaha, keep watching. . . . . .

2. Reconstruct yesterday’s example

The following is the source code of yesterday’s Js part:

Copy code The code is as follows:

(function($){
$.fn.bigbear = function(opts){
         opts = $.extend({},$.fn.bigbear.defaults,opts) ;
         return this.each(function(){
            var elem = $(this) ;
              elem.find("span").text(opts["title"]) ;
               $.get(opts["url"],function(data){
                    elem.find("div").text(data["text"]) ;
             }) ;
         }) ;
} ;
$.fn.bigbear.defaults = {
Title: "This is a simple test" ,
  url: "data.json"
} ;
})(jQuery) ;

Let’s analyze it line by line:

First determine the function of this plug-in

(1), display the title text information we set.

(2), dynamically obtain content information in an asynchronous manner.

Okay! Once the requirements are clear, we can start the discussion. From the above code, it is easy to see that the logical organization is very loose and the procedural thinking is obvious, so the first step is to put our functional requirements

Efficiently organized in classes. Look at the refactored code below:

Copy code The code is as follows:

$(function(){
    $("#bb").bigbear() ;
}) ;
(function($){
    $.fn.bigbear = function(opts){
        opts = $.extend({},$.fn.bigbear.defaults,opts) ;
        return this.each(function(){
            var elem = $(this) ;
            var bb = new BigBear(elem,opts) ;
            bb.getElem().trigger("data") ;
        }) ;
    } ;
    $.fn.bigbear.defaults = {
        title : "这是一个简单的测试" ,
        url : "data.json"
    } ;
})(jQuery) ;
function BigBear(elem,opts){
    this.elem = elem ;
    this.opts = opts ;
    this.init() ;
} ;
var bbProto = BigBear.prototype ;
bbProto.getElem = function(){
    return this.elem ;
} ;
bbProto.getOpts = function(){
    return this.opts ;
} ;
bbProto.init = function(){
    var that = this ;
    this.getElem().on("data",function(){
        that._setTitle(that.getOpts()["title"]) ;
        $.get(that.getOpts()["url"],function(result){
            that.getElem().find("div").text(result["text"]) ;
        }) ;
    }) ;
} ;
bbProto._setTitle = function(text){
    this.getElem().find("span").text(text) ;
} ;

　　哈哈哈，是不是代码多了不少，其实这种方式就是面向对象的角度看问题，先去分析功能需求，然后设计我们的类，虽然说我们不可能一下设计得很出色，

但是看问题角度改变了，我们的代码可读性强了，以及更好地进行维护这样我们的目的也就达到了。

　　以下是是摘自“Bootstrap”Js部分的相关源码实现，如下图：

不难看出也是相似的实现方式，通过类来维护我们插件的主要逻辑。

（三），增加新功能，引出额外的类

　　现在需求增加了，需要在体验上有所变化，加载数据时有“loading”效果。

　　实现思路可以这样，在原始的内容区把文字设置成“装载数据中。。。。”的字样，然后引入一个新的类，如下：

复制代码 代码如下:

function Overlay(){

} ;
var olProto = Overlay.prototype ;
olProto.show = function(){} ;
olProto.hide = function(){} ;
// 具体实现就不写了

　　好了，遮罩层已经有了，现在我们怎么集成进来那？我们用组合的方式接入进来，如下：

复制代码 代码如下:

 function BigBear(elem,opts){
     this.elem = elem ;
     this.opts = opts ;
     this.overlay = new Overlay() ;
     this.init() ;
 } ;
 var bbProto = BigBear.prototype ;
 bbProto.getElem = function(){
     return this.elem ;
 } ;
 bbProto.getOpts = function(){
     return this.opts ;
 } ;
 bbProto.init = function(){
     var that = this ;
     var loadingText = "数据装载中。。。" ;
     this.getElem().on("data",function(){
         that._setTitle(that.getOpts()["title"]) ;
         that.overlay.show() ;
         that.getElem().find("div").text(loadingText) ;
         $.get(that.getOpts()["url"],function(result){
             that.overlay.hide() ;
             that.getElem().find("div").text(result["text"]) ;
         }) ;
     }) ;
 } ;
 bbProto._setTitle = function(text){
     this.getElem().find("span").text(text) ;
 } ;

　　到此只为我们的功能就算是结束了，这样写的插件，我相信比第一个版本好很多，当然这不是最优的实现，需要从细节上不断重构，但是这种方式是一种可选的开发插件的方式。

　　以下是完整的代码：

复制代码 代码如下:

$(function(){
    $("#bb").bigbear() ;
}) ;
(function($){
    $.fn.bigbear = function(opts){
        opts = $.extend({},$.fn.bigbear.defaults,opts) ;
        return this.each(function(){
            var elem = $(this) ;
            var bb = new BigBear(elem,opts) ;
            bb.getElem().trigger("data") ;
        }) ;
    } ;
    $.fn.bigbear.defaults = {
        title : "这是一个简单的测试" ,
        url : "data.json"
    } ;
})(jQuery) ;
function BigBear(elem,opts){
    this.elem = elem ;
    this.opts = opts ;
    this.overlay = new Overlay() ;
    this.init() ;
} ;
var bbProto = BigBear.prototype ;
bbProto.getElem = function(){
    return this.elem ;
} ;
bbProto.getOpts = function(){
    return this.opts ;
} ;
bbProto.init = function(){
    var that = this ;
    var loadingText = "数据装载中。。。" ;
    this.getElem().on("data",function(){
        that._setTitle(that.getOpts()["title"]) ;
        that.overlay.show() ;
        that.getElem().find("div").text(loadingText) ;
        $.get(that.getOpts()["url"],function(result){
            that.overlay.hide() ;
            that.getElem().find("div").text(result["text"]) ;
        }) ;
    }) ;
} ;
bbProto._setTitle = function(text){
    this.getElem().find("span").text(text) ;
} ;
function Overlay(){
} ;
var olProto = Overlay.prototype ;
olProto.show = function(){} ;
olProto.hide = function(){} ;
// 具体实现就不写了

本文暂时先到这里了，小伙伴们是否对插件化开发javascript有了新的认识了呢。