Function useWorkbookFormat

useWorkbookFormat(workbook: IWorkbook | null): string | null
Tracks the format a workbook is bound to (Origin.getFormat()) as React state.
Parameters
- workbook: IWorkbook | null
  The workbook to track, or null.
Returns string | null
The resolved format key (e.g. 'SheetXL'), the path's extension when no key has been resolved yet, or null for an unbound workbook.

Remarks
A format KEY, not a full format type — resolving one to the other needs the registry (getWriteFormats({ search: key })), which is async and a concern of whoever is asking.

Follows the workbook to whichever origin it lives in, so chrome that names the current format (a Save As menu, a status bar) updates the moment a Save As moves the workbook rather than going stale until the next mount.