JavaScript遍历对象Key与Value的三种常用方法

let obj = {
    name: 'Kamen',
    age: '23',
    hobby: 'eat eat eat'
  }

//遍历对象属性
Object.keys(obj).forEach(key => {
    console.log(key)
  })

// 简单数组
const arr = ['a', 'b', 'c'];
console.log(Object.keys(arr)); // console: ['0', '1', '2']

// 类数组对象
const obj = { 0: 'a', 1: 'b', 2: 'c' };
console.log(Object.keys(obj)); // console: ['0', '1', '2']

// 具有随机键顺序的类数组对象
const anObj = { 100: 'a', 2: 'b', 7: 'c' };
console.log(Object.keys(anObj)); // console: ['2', '7', '100']

// getFoo 是一个不可枚举的属性
const myObj = Object.create({}, {
  getFoo: {
    value() { return this.foo; }
  }
});
myObj.foo = 1;
console.log(Object.keys(myObj)); // console: ['foo']

//遍历对象属性值
Object.values(obj).forEach(val => {
  console.log(val)
})

const obj = { foo: "bar", baz: 42 };
console.log(Object.values(obj)); // ['bar', 42]

// Array-like object
const arrayLikeObj1 = { 0: "a", 1: "b", 2: "c" };
console.log(Object.values(arrayLikeObj1)); // ['a', 'b', 'c']

// Array-like object with random key ordering
// When using numeric keys, the values are returned in the keys' numerical order
const arrayLikeObj2 = { 100: "a", 2: "b", 7: "c" };
console.log(Object.values(arrayLikeObj2)); // ['b', 'c', 'a']

// getFoo is a non-enumerable property
const myObj = Object.create(
  {},
  {
    getFoo: {
      value() {
        return this.foo;
      },
    },
  },
);
myObj.foo = "bar";
console.log(Object.values(myObj)); // ['bar']

for( let key in obj ){
    //遍历对象属性
    console.log(key)
    //遍历对象属性值
    console.log(obj[key])
  }

Object.prototype.pet = 'open'
for( let key in obj ){
  console.log(key)
  console.log(obj[key])
}
console.log(obj)

Object.prototype.pet = 'open'
  for( let key in obj ){
    if (obj.hasOwnProperty(key) === true){
      console.log(key)
      console.log(obj[key])
    }
  }
  console.log(obj)