es6(16)--Decorator

 //Decorator:修饰器，是一个函数用来修改类的行为
 {
     //只读
     let readonly=function(target,name,descriptor){
         descriptor.writable=false;
         return descriptor;
     };
     class Test{
         @readonly
         time(){
             return '2017-03-11'
         }
     }
     let test=new Test();
     // test.time=function(){
     //     console.log('reset time');
     // }
     console.log(test.time())
 }
 {
     let typename=function(target,name,descriptor){
         target.myname="hello";
     }
     @typename
     class Test{

     }
     console.log(Test.myname)
 }
 //常用的修饰器的js库，core-decorators;cnpm install core-decorators --save-dev
 {
     let log=(type)=>{
         return function(target,name,descriptor){
             let src_method=descriptor.value;
             descriptor.value=(...arg)=>{
                 src_method.apply(target,arg);
                 console.info(`log ${type}`);
             }
         }
     }
     class AD{
         @log('show')
         show(){
             console.info('ad is show')
         }
         @log('click')
         click(){
             console.info('ad is click')
         }
     }
     let ad=new AD();
     ad.show();
     ad.click();
 }