Read the YAML metadata (and any common output.yaml file)
for the document and return the output format that will be
generated by a call to render.
default_output_format(input, encoding = getOption("encoding"))Input file (Rmd or plain markdown)
The encoding of the input file; see
file
A named list with a name value containing the format
name and an options value that is a list containing
all the options for the format and their values. An
option's default value will be returned if the option isn't
set explicitly in the document.
This function is useful for front-end tools that require
additional knowledge of the output to be produced by
render (e.g. to customize the preview
experience).