for in和for of的简单区别

            //for in可以遍历数组和对象,但是for of只能遍历数组,不可以遍历对象
            
            var arr = [1,4,5,6,7,8];
            var obj = {
                name:‘za‘,
                age:19,
                say:function(){
                    console.log(‘hello‘)
                }
            }
            
            //for in循环出的是key,
            for(var i in arr){
                console.log(‘索引值‘,i);  //索引值 0 1 2 3 4 5 
            }
            for(var i in obj){
                console.log(‘属性名‘,i);  //属性值 name age say
            }
            
            //for of循环出的是value
            for (var item of arr){
                console.log(‘数组项‘,item);  //数组项 1 4 5 6 7 8
            }
            for(var item of obj){
                console.log(item);  //报错obj is not iterable,对象不可用for of
            }