JS对象的遍历方法

var obj = { 
   '0':'a', '1':'b', '2':'c'};
for(let i in obj){ 
   
    console.log(i,":",obj[i]);//{0:a,1:b,2:c}
}

var obj = { 
   '0':'a', '1':'b', '2':'c'};
Object.keys(obj).forEach(function(key){ 
   
	console.log(key,obj[key]);//{0:a,1:b,2:c}
}

var obj = { 
   '0':'a','1':'b','2':'c'};

Object.getOwnPropertyNames(obj).forEach(function(key){ 
   
    console.log(key,obj[key]);
});