Angular HttpPromise: difference between `success`/`error` methods and `then`'s arguments

Question

According to AngularJS doc, calls to $http return the following:

Returns a promise object with the standard then

Answer 1

Official Notice: success and error have been deprecated, please use the standard then method instead.

Deprecation Notice: The $http legacy promise methods success and error have been deprecated. Use the standard then method instead. If $httpProvider.useLegacyPromiseExtensions is set to false then these methods will throw $http/legacy error.

link: https://code.angularjs.org/1.5.7/docs/api/ng/service/$http

screenshot: view the screenshot