Single-Sign-On (SSO) for JavaScript Excel custom functions?

Question

Custom functions (https://docs.microsoft.com/en-us/office/dev/add-ins/excel/custom-functions-overview) execute in a runtime different from the usual office-js runtime for, i.e., task pane add-ins. Task pane add-ins can use 'Office.context.auth.getAccessTokenAsync' for SSO but as far as I can see there is no such function available for custom functions add-ins.

I'm aware that custom functions add-ins can open a dialog for authorization but this is not the same as SSO where no prompt for credentials would be required.

Is there a way to perform SSO within a custom functions add-in?

Answer 1

I'm afraid that SSO is not yet supported in custom functions. You will have to implement your own login dialog and, optionally, pass the token to the task pane by storing it in AsyncStorage.