// Bucket name in the format of `BucketName-APPID` (`APPID` is required), which can be viewed in the COS console at https://console.tencentcloud.com/cos5/bucket.
let bucket = "examplebucket-1250000000";
// The location of the object in the bucket, i.e., the object key
let cosPath = "exampleobject";
// URL request parameters
let requestParameters = {"test1k":"test1v", "test2k":"test2v"};
try {
  // Get a pre-signed URL for downloading objects
  String objectUrl = await Cos.getDefaultService().getPresignedUrl(
    bucket, 
    cosPath, 
    {
      parameters: requestParameters
    }
  );
} catch (e) {
  // An exception will be reported in case of failure. Process the business logic accordingly.
  console.log(e);
}