for of和for in的区别?

区别:

区别	for of	for in
数组	值	索引
对象	\	键

• for in可以遍历数组,也可以遍历对象

  • 遍历数组拿到的是索引

    let arr=['a','b','c','d','e']
    for(let i in arr){
        console.log(i)//索引0,1,2,3,4
        console.log(arr[i])//值a,b,c,d,e
    }
    

  • 遍历对象拿到的是键

    let  obj={name:'张三',age:18}
    for(let i in obj){
        console.log(i)//键 name,age
        console.log(obj[i])//值 张三,18
    }
    

• for of 只能遍历数组,拿到的是值

    for(let i of arr){
        console.log(i)//值a,b,c,d,e
    }