But you're impatient. You like living on the edge. You drink wine from the bottle. You want some stuff to work now! One of the things not in the 4.0beta1 API is editing. If you look at the docs for a FeatureLayer, it has no editing capabilities at the moment. It will, just not yet. That's ok though. You're a developer... you got this.
Softwhere Developer at Esri working on cool stuff!
ArcGIS Web Development - https://amzn.to/2EIxTOp
Born and raised in East L.A.