You can listen for the "edits" event directly on the source layer
Unfortunately that does not work, any other idea ?
It appears that you are using the Editor widget, so I think what you want is to capture the "create" event of the underlying SketchViewModel instance. In that case, it would be something like:
editor.viewModel.sketchViewModel.on("create", function(evt) {
if (evt.state == "complete") {
//do something with evt.graphic here
}
});