1.for of 無(wú)法遍歷對(duì)象

var obj={

    name:"jack",

    age:18,

    weight:120

}

for(let i in obj){

    console.log(i,obj[i],"for in")

}

for(let j of obj){

    console.log(j,obj[j],"for of")

}

打印后提示 obj is not iterable

遍歷對(duì)象

2.遍歷輸出結(jié)果不同

for in 遍歷數(shù)組的索引，for of直接遍歷數(shù)組的值

var arr=["jack","nick","neo","leo"]

for(let i in arr){

    console.log(i)

}

console.log("----------------------------")

for(let j of arr){

    console.log(j)

}

遍歷數(shù)組

遍歷字符串

let name="jacky"
for(var i in name){
    console.log(i); 
}
console.log('----------------------');
for(var j of name){ 
    console.log(j);
}

遍歷字符串

3.for in 會(huì)遍歷自定義屬性，而for of不會(huì)

var arr = ["jack","nick","neo","leo"]

arr.name = "mike";

for(var i in arr){

    console.log(i,arr[i]);  

}

console.log('----------------------');

for(var j of arr){  

    console.log(j);

}

for in 輸出了name，而for of沒(méi)有輸出，可能是由于上面說(shuō)的for of無(wú)法輸出對(duì)象的原因？有錯(cuò)誤請(qǐng)大佬指出~謝謝！

遍歷自定義屬性