ts学习笔记（5）

属性装饰器

function decorate(param:any){
  param.prototype.test='zz'
}
@decorate
class Test{
    public  name:string;

    constructor(name:string){
       this.name=name;
    }
}
var x=new Test('zz')
console.log(x.test)
//打印xx

还有一种是写在属性上面

function decorate(param:any){
 return function(target,attr){
     console.log(target)
     console.log(attr)
    target.attr=param;
 }
}
class Test{
    @decorate('xx')
    public  name:string;

    constructor(name:string){
       this.name=name;
    }
}
var x=new Test('zz')
console.log(x)
//{name:'xx'}

类装饰器

function decorate(target:any){
 return class extends target{
  name="cc"
 }
}
@decorate
class Test{
   
    public  name:string;

    constructor(name:string){
       this.name=name;
    }
}
var x=new Test('zz')
console.log(x)
//{name:'cc'}

方法装饰器

function decorate(param:any){
 return function(target:any,methodName:any,desc:any){
    console.log(target)//类
    console.log(param)//参数
    console.log(methodName)//方法名
    var oMethod=desc.value;
    console.log(oMethod)//方法
    desc.value=()=>{console.log('修改后的方法')}
 
 }
}

class Test{
   
    public  name:string;

    constructor(name:string){
       this.name=name;
    }
    @decorate("yy")
    add(){
        console.log(12)
    }
}
var x=new Test('zz')
x.add()
//修改后的方法

参数装饰器

function decorate(param:any){
 return function(target:any,methodName:any,paramsIndex:any){
    console.log(target)//类
    console.log(param)//参数
    console.log(methodName)//方法名
    console.log(paramsIndex)
 
 }
}

class Test{
   
    public  name:string;

    constructor(name:string){
       this.name=name;
    }
    add(@decorate('xx') str:string){
        console.log(str)
    }
}
var x=new Test('zz')
x.add('yy')
//yy