you will not need to use these. Instead, see
html_setup() for methods that cover most use-cases.
register_knitr_output_hooks(set = TRUE, chunk_hook = NULL)
register_knitr_js_engine(set = TRUE)
FALSE the output hook or JS engine are returned rather than
setting via knitr directly.
Chunk hook to be applied after the js4shiny chunk hook
is applied to the chunk output. If
NULL, then the current chunk hook
is used. Only applies when
set = TRUE.