SOURCE

obj ={
    'a':1,
    'b':2,
    'c':3
}
arr =[1,2,3,5]
console.log(obj)
for( key of arr)
{
    console.log(key)
}


obj[Symbol.iterator] = function () {
 
        let aa = Object.values( obj ) //获取对象所有的值以数组返回
       // console.log( aa,'aa' )
        let index = 0
 
        return {
            //a:123
            next:function(){
                if( index >= aa.length ){
                    return { value:undefined,done:true }
                }else{
                    return { value:aa[index++],done:false }
                }
                              
            }
        }
        }

for( key of obj)
{
    console.log(key)
}