模仿JQuery.extend函数扩展自己对象

    
    
    
    

     
     
     
      MyMath.extend 
     
     
     
     =
     
     
     
      
     
     
     
     function
     
     
     
     (){
 
     
     
     
     //
     
     
     
      copy reference to target object
     
     
     
     

     
     
     
      
     
     
     
     var
     
     
     
      target 
     
     
     
     =
     
     
     
      arguments[
     
     
     
     0
     
     
     
     ] 
     
     
     
     ||
     
     
     
     
 {}, i 
     
     
     
     =
     
     
     
      
     
     
     
     1
     
     
     
     , length 
     
     
     
     =
     
     
     
      arguments.length, deep 
     
     
     
     =
     
     
     
      
     
     
     
     false
     
     
     
     , options;
 
 
     
     
     
     //
     
     
     
      Handle a deep copy situation
     
     
     
     

     
     
     
      
     
     
     
     if
     
     
     
      (
     
     
     
     typeof
     
     
     
      target 
     
     
     
     ===
     
     
     
      
     
     
     
     "
     
     
     
     boolean
     
     
     
     "
     
     
     
     ) {
 deep 
     
     
     
     =
     
     
     
      target;
 target 
     
     
     
     =
     
     
     
      arguments[
     
     
     
     1
     
     
     
     ] 
     
     
     
     ||
     
     
     
     
 {};
 
     
     
     
     //
     
     
     
      skip the boolean and the target
     
     
     
     

     
     
     
      i 
     
     
     
     =
     
     
     
      
     
     
     
     2
     
     
     
     ;
 }
 
 
     
     
     
     //
     
     
     
      Handle case when target is a string or something (possible in deep copy)
     
     
     
     

     
     
     
      
     
     
     
     if
     
     
     
      (
     
     
     
     typeof
     
     
     
      target 
     
     
     
     !==
     
     
     
      
     
     
     
     "
     
     
     
     object
     
     
     
     "
     
     
     
      
     
     
     
     &&
     
     
     
      
     
     
     
     !
     
     
     
     jQuery.isFunction(target)) 
 target 
     
     
     
     =
     
     
     
      {};
 
 
     
     
     
     //
     
     
     
      extend jQuery itself if only one argument is passed
     
     
     
     

     
     
     
      
     
     
     
     if
     
     
     
      (length 
     
     
     
     ==
     
     
     
      i) {
 target 
     
     
     
     =
     
     
     
      
     
     
     
     this
     
     
     
     ;
 
     
     
     
     --
     
     
     
     i;
 }
 
 
     
     
     
     for
     
     
     
      (; i 
     
     
     
     <
     
     
     
      length; i
     
     
     
     ++
     
     
     
     ) 
 
     
     
     
     //
     
     
     
      Only deal with non-null/undefined values
     
     
     
     

     
     
     
      
     
     
     
     if
     
     
     
      ((options 
     
     
     
     =
     
     
     
      arguments[i]) 
     
     
     
     !=
     
     
     
      
     
     
     
     null
     
     
     
     ) 
 
     
     
     
     //
     
     
     
      Extend the base object
     
     
     
     

     
     
     
      
     
     
     
     for
     
     
     
      (
     
     
     
     var
     
     
     
      name 
     
     
     
     in
     
     
     
      options) {
 
     
     
     
     var
     
     
     
      src 
     
     
     
     =
     
     
     
      target[name], copy 
     
     
     
     =
     
     
     
      options[name];
 
 
     
     
     
     //
     
     
     
      Prevent never-ending loop
     
     
     
     

     
     
     
      
     
     
     
     if
     
     
     
      (target 
     
     
     
     ===
     
     
     
      copy) 
 
     
     
     
     continue
     
     
     
     ;
 
 
     
     
     
     //
     
     
     
      Recurse if we're merging object values
     
     
     
     

     
     
     
      
     
     
     
     if
     
     
     
      (deep 
     
     
     
     &&
     
     
     
      copy 
     
     
     
     &&
     
     
     
      
     
     
     
     typeof
     
     
     
      copy 
     
     
     
     ===
     
     
     
      
     
     
     
     "
     
     
     
     object
     
     
     
     "
     
     
     
      
     
     
     
     &&
     
     
     
      
     
     
     
     !
     
     
     
     copy.nodeType) 
 target[name] 
     
     
     
     =
     
     
     
      jQuery.extend(deep, 
     
     
     
     //
     
     
     
      Never move original objects, clone them
     
     
     
     

     
     
     
      src 
     
     
     
     ||
     
     
     
      (copy.length 
     
     
     
     !=
     
     
     
      
     
     
     
     null
     
     
     
      
     
     
     
     ?
     
     
     
      [] : {}), copy);
 
 
     
     
     
     //
     
     
     
      Don't bring in undefined values
     
     
     
     

     
     
     
      
     
     
     
     else
     
     
     
      
 
     
     
     
     if
     
     
     
      (copy 
     
     
     
     !==
     
     
     
      undefined) 
 target[name] 
     
     
     
     =
     
     
     
      copy;
 
 }
 
 
     
     
     
     //
     
     
     
      Return the modified object
     
     
     
     

     
     
     
      
     
     
     
     return
     
     
     
      target;
 };
    
    
    
    

 

 

调用方法

 

代码

    
    
    
    

     
     
     
      MyMath.extend({
 Mul: 
     
     
     
     function
     
     
     
     (a, b){
 
     
     
     
     return
     
     
     
      a 
     
     
     
     *
     
     
     
      b;
 },
 Div: 
     
     
     
     function
     
     
     
     (a, b){
 
     
     
     
     return
     
     
     
      a 
     
     
     
     /
     
     
     
      b;
 }
 });