ES6 - Map 方法 keys()

該函式返回一個 迭代器，它包含 map 物件中每個元素的鍵

語法

keys() 的語法如下所示

map_name.keys()

示例

<script>
   let andy = {ename:"Andrel"},
      varun = {ename:"Varun"},
      prijin = {ename:"Prijin"}

   let empJobs = new Map([
      [andy,'Software Architect'],
      [varun,'Developer']]
   );

   for(let emp of empJobs.keys()){
      console.log(emp.ename)
   }
</script>

上面程式碼的輸出如下所示 −

Andrel
Varun