Object.keys()：返回键名的遍历器

let obj = {
    name: 'lucy',
    age: 18,
    hobby: ['魔方', '代码']
}
console.log(Object.keys(obj));
//[ 'name', 'age', 'hobby' ]

Object.values()：返回键值的遍历器

let obj = {
    name: 'lucy',
    age: 18,
    hobby: ['魔方', '代码']
}
console.log(Object.values(obj));
//[ 'lucy', 18, [ '魔方', '代码' ] ]

Object.entries()：返回键值对的遍历器

let obj = {
    name: 'lucy',
    age: 18,
    hobby: ['魔方', '代码']
}
console.log(Object.entries(obj));
//[ [ 'name', 'lucy' ], [ 'age', 18 ], [ 'hobby', [ '魔方', '代码' ] ] ]