简述js中 for in 与 for of 区别

 for in、for of的区别:

遍历数组：

let arr = [1,2,3,4,"d","f","g",""," "]; for(let val of arr){ console.log(val); } for(let index in arr){ console.log(index,arr[index]); }

控制台结果如下：

遍历对象： 

let obj = { "name":"Ghui", "sex":0, "age":24, say:function say(){ console.log(this.name + "说：我是" + this.name); } } for(let key in obj){ console.log(key,obj[key]) } for(let index of obj){ console.log(index) }

控制台结果如下： 

遍历字符串

let str = "Ghui"; for(let strindex in str){ console.log(s) } for(let string of str){ console.log(string) }

控制台结果如下：

总结：

for in 取 key，for of 取 value

for of 只能用于数组遍历，for in还可以遍历对象