This seems like a moderately complex undertaking. I wish to automatically set column widths in my xlsx exports.

The logic is, roughly:

1. Find out the data type of each column. For some data types such as dates and numerics, there are prefered (fixed) column width and number formats.
2. For strings, a maximum width should be enforced.
3. For other odd balls, ignore them?

This means taking the input (data.table or workbook object), examine each column, add_styles, and save it. Probably just data.table, as workbook object contains formatting information already and messing with it just isn't worth it.

Maybe make as.Time recognize date-time strings formatted with AM/PM indicator.

The time portion should be recognized with %I:%M %p.