一種angular的方法級的緩存注解（裝飾器）

@Cacheable(value="'accountCache_'+#userName")// 緩存名叫 accountCache_USERNAME  
public Account getAccountByName(String userName) {  
// @@@@
return acount;  
} 

@cacheable(111)
getSecondLeftMenu(topMenuId: number){
return 1111;
}

export function cacheable(timeout:number) {
  return function (target: any, key: string, descriptor: any) {
     const originalMethod = descriptor.value;
     descriptor.value = function (...args: any[]) {
//把傳入的參數(shù)和被調(diào)的函數(shù)名一起組成存儲的主鍵
       const paramStr = args.map(a => JSON.stringify(a)).join();
       const keyStr=key+"start$$"+(paramStr||"")+"-$$end";
       let resultStr=localStorage.getItem(keyStr);
       if (!!resultStr) {
         let resultValue=JSON.parse(resultStr);
          let now=new Date() as any;
//把緩存時的時間和當(dāng)前的時間進行對比，如果沒有超時，則直接返回
          let old2=(new Date(resultValue.date)) as any;
          let delt=now - old2;
          if (delt<(timeout*1000)) {
            return Promise.resolve(resultValue.value);
          }
       }
//超時時，調(diào)用原方法，并記錄返回結(jié)果，這里我們的返回均是promise對象
       var result = originalMethod.apply(this, args);
       result.then(data=>{
        let dd={
          date:new Date(),
          value:data
        }
        localStorage.setItem(keyStr,JSON.stringify(dd))
        return Promise.resolve(data);
       },data=>{
        return Promise.reject(data);
       })
       return result;
     }
     return descriptor;
    }
}