Precompute formatted label columns from expressions and attach them to the
widget data. Accepts named expressions like x = round(varx, 2) or
y = format(varY, big.mark = ","). The formatted columns are added to
d3po$x$data with names __label_<name> and registered in
d3po$x$formatted_cols for the renderer to use.
po_format(d3po, ...)Either the output of d3po() or d3po_proxy().
Named formatting expressions (as quosures). Each name should
correspond to an aesthetic (e.g. x, y, tooltip, etc.).