Return download URL from nested firebase function

I used a local variable to set a value from firebase function but it doesn't work. I return URL following this code but I don't know how to read firebase object:

export var downloadFile = (folderName, fileName) => {
  // Create a reference to the file we want to download
  var starsRef = storageRef.child(`${folderName}/${fileName}`);


  // Get the download URL
return  starsRef.getDownloadURL().then((url) => {
    // Insert url into an <img> tag to "download"
    return url
  })

}

The output will be like this:

How can I return URL or How can I read firebase object

via Amir hossein gholzam