Long ago, es6 Promises didn't used to work in worker scripts for character sheets. Does anyone know if this was ever fixed? It would be nice to not have to explicitly use callbacks for all the asynchronous parts.
Unfortunately it is not possible. Not sure if it's a technical hurdle or what, but the problem is that using anything asynchronous (other than sheetworker functions) breaks the link between that run of the code and the sheet in question.