HarmonyOS 怎样遍历形似Map<string,Array<Object>>这样的map变量的所有key

let groupMap:Map<string,Array<String>> = new Map<string,Array<String>>() 
let arr1:Array<String> = new Array<String>() 
arr1.push('我是测试1') 
arr1.push('我是测试2') 
 
let arr2:Array<String> = new Array<String>() 
arr2.push('我是测试3') 
arr2.push('我是测试4') 
 
groupMap.set('我是key1',arr1) 
groupMap.set('我是key2',arr2) 
 
for (let key of groupMap.keys()) { 
  console.log(key) 
}