# JS Chapter4_物件 ###### tags: `JS鐵人賽` ### 物件使用時機 詳細描述一個東西內部資訊 ### 物件格式 ```javascript= //物件格式 let home = { //屬性 : '值', //屬性 : '值', motherName : 'Mary', fatherName : 'Tom', isWakeUp : 'False', dogs : 3, }; ``` ### 讀取物件 ```javascript= let home = { motherName : 'Mary', fatherName : 'Tom', isWakeUp : 'False', dogs : 3, }; //讀取物件值 let tomDogs = home.dogs; console.log(tomDogs); ``` ```javascript= //另一種讀取方式－字串 console.log('motherName') ``` ```javascript= //讀取進階用法 let a = 'motherName'; console.log(home[a]) ``` 如果面臨到需要讀取Json資料則會如以下情況 ```javascript= //json陣列寫法 let home = { myName : 'Jack', '001' : 'Mary', }; console.log(home); //想讀取001資料不得用此方式→console.log(home.001); console.log(home['001']); ``` ### 新增物件屬性 ```javascript= let home = {}; home.myName = 'Mary'; home.dogs = 3; home.isWakeup = false; console.log(home); ``` ### 修改物件值 ```javascript= let home = { motherName : 'Mary', fatherName : 'Tom', isWakeUp : 'False', dogs : 3, }; //修改物件值 home.motherName = 'Jane'; home.dogs+=1; console.log(home); ``` ### 刪除物件值 ```javascript= let home = { motherName : 'Mary', fatherName : 'Tom', isWakeUp : 'False', dogs : 3, }; delete home.dogs; console.log(home); //由於dogs值被刪除，因此會顯示undefined console.log(home.dogs); ``` ### 使用鍵值操作物件 https://www.delftstack.com/zh-tw/howto/javascript/javascript-key-value-array/ https://ithelp.ithome.com.tw/articles/10219496 **進階操作DEMO－使用函數回傳物件** https://codepen.io/TODelusion/pen/qBxwzMX?editors=0012