JS遍历对象、map及数组

遍历对象

for in

const user = {
  id: 1,
  name: 'Joe.Ye',
  age: 18
}

for(let key in user) {
  console.log(key + ': ' + user[key])
}

Object.keys

• Object.keys(obj)
• Object.values(obj)

返回obj对象的key组成的字符串数组及value组成的字符串数组

const user = {
  id: 1,
  name: 'Joe.Ye',
  age: 18
}

console.log(Object.keys(user))
console.log(Object.values(user))

Object.getOwnPropertyNames(obj)

返回一个数组，包含对象自身的所有属性（包含不可枚举属性）

const user = {
  id: 1,
  name: 'Joe.Ye',
  age: 18
}

Object.getOwnPropertyNames(user).forEach(function(key){
  console.log(key + ': ' + user[key])
})

遍历map

for in

var map = {
  "name": "Joe.Ye",
  "homepage": "http://www.appblog.cn"
};

for (var key in map) {
  console.log("map[" + key + "] = " + map[key]);
}