data数据缓存.html

<!DOCTYPE html>
<html>
<head lang="en">
  <meta charset="UTF-8">
  <title></title>

</head>
<body>
<p></p>
<script>
  (function(){
    function extend(obj){
      var other= [].slice.call(arguments,1);
      if(!other){
        return;
      }
      for(var i=0;i<other.length;i++){
        var cloneObj=other[i];
        for(var key in cloneObj){
          if(typeof cloneObj[key]==='function'){
            obj[key]=cloneObj[key];
          }else if(typeof cloneObj[key]==='object'){
            obj[key]=cloneObj[key] instanceof Object?{}:[];
            extend(obj[key],cloneObj[key]);
          }else{
            obj[key]=cloneObj[key];
          }
        }
      }
    }
    var Data=function(){
      Object.defineProperty(this.cache={},0,{
        get:function(){
          return {};
        }
      });
      this.expando='Data'+Math.random();
    }
    Data.uid=0;
    Data.prototype={
      key:function(elem){
        var val=elem[this.expando],
            descriptor={};
        if(!val){
//          val=Data.uid++;
            val=++Data.uid;
          try{
//            descriptor={value:val};
            descriptor[this.expando]={value:val};
            Object.defineProperties(elem,descriptor);//此处不是很熟悉
          }catch(e){
            descriptor[this.expando]=val;
            extend(elem,descriptor);
          }
        }
        if(!this.cache[val]){
          this.cache[val]={};
        }
        return val;
      },
      get:function(elem,key){
        var val=this.key(elem),
            cache=this.cache[val];
        if(!key){
          return this.cache[val];
        }
        if(cache){
          return cache[key]?cache[key]:{};
        }
      },
      set:function(elem,key,value){
        var val=this.key(elem),
            cache=this.cache[val];
            console.log(cache);
            cache[key]=value;
      }
    }
    var data=new Data();
    var p=document.getElementsByTagName('p')[0];
    data.set(p,'name','hello');
    console.log(data.get(p,'name'));
    window.data=data;
    var a={
          b:0,
          name:'hello',
          go:function(){
            alert('你好');
          },
          friends:['xiaoming','tiantain','linlin'],
        };
    var b={};
    extend(b,a);
    console.log(b);
  })()
</script>
</body>
</html>