No offense but TensorFlow's Dataset API documentation also sucks. This combined with bad API design (that actually can be used as case study for bad design in classrooms) is disaster in making. For example, shuffle() takes a mysterious argument. Why? It's not to be found in docs except that it should be more than items in dataset. Why can't shuffle() just be shuffle() and why do I now always have to remember passing correct parameter for rest of my life? Whatever. I still don't get what exactly repeat() does. Does it rewinds back to start when you reach past end? Why you need it? Why not just stick to epochs? Why make things complicated with steps vs epochs anyway? Docs gives zero clue. Then there are whole bunch of mysteriously named unexplained methods like make_one_shot_iterator() or from_tensor_slices(). Why is make_one_shot_iterator() not just iterator()? Why do I have to rebuild dataset using from_tensor_slices()? The docs are designed with a point of view "take all these code calling mysteriously designed APIs, copy-paste and don't bother too much about understanding what those APIs really do". It really sucks.
IMO, shuffle is something they did really fine. Unlike PyTorch datasets, TF allows streaming unbounded data. For something like this work with shuffle, it must cache some data before passing it down the pipeline. You specify how much in the argument.
This may not seem useful this conventional training, where you usually work with a fixed amount of samples you know beforehand. But there may be cases where this is not true (for instance, in some special cases of augmentation) - the streaming part is useful but then you must use this caching trick.
But I agree API naming is not stellar, or at least should come with better documentation.