// Bucket name, which consists of bucketname-appid (appid must be included), can be viewed in the COS console. https://console.tencentcloud.com/cos5/bucket
let bucket = "examplebucket-1250000000";

let request = new ListObjectsRequest(bucket);
// Obtain all files in the dir directory: request.prefix = "dir/"
// Obtain all files in the root directory: request.prefix = "";
request.prefix = "dir/" 
try {
  let result = await CosXmlBaseService.default().listObject(request)
  // result includes http headers, etc.
} catch (e) {
  // Exception
  // Processing
}