LeanCloud reported an error cannot readproperty’ _ thenuncallbacks’ of undefined

  node.js, question

The code is as follows:

var file = new AV.File("test.png", req.files.file);
 file.save()
 .then(function(response) { console.log(response._url);   }, function(error) { console.log(error);   });

The error is as follows:

TypeError: Cannot read property '_thenRunCallbacks' of undefined

The same mistake was reported.