[Bug]: `tm_t_shift_by_grade` takes too long when "adding to" or downloading a report

[averissimo]

What happened?

When testing the safety app in teal gallery, it takes more than 15s for the report to be added.

The root cause is the rendering of the HTML of the data in teal.reporter package. The toHTML and to_rmd rendering functions are not efficient for this data structure.

sessionInfo()

Relevant log output

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[donyunardi]

I can reproduce this. It's about 10-15 seconds of wait (I tried couple times) when Add to Report.

[averissimo]

Maybe we could fix this for data.frame only with knitr::knit_print or knitr::kable (both surrounded by <pre> tag).

Benchmarks

Benchmarks of possible options:

cached_tt <- rtables::df_to_tt(iris)

bench::mark(
  reporter_step1 = rtables::df_to_tt(iris),
  reporter_step2 = rtables.officer::tt_to_flextable(cached_tt),
  knit_print = knitr::knit_print(flextable::flextable(iris)),
  officer = officer::to_html(flextable::flextable(iris)),
  knitr = knitr::kable(iris),
  check = FALSE
)
#> # A tibble: 5 × 13
#>   expression          min   median `itr/sec` mem_alloc `gc/sec` n_itr  n_gc
#>   <bch:expr>     <bch:tm> <bch:tm>     <dbl> <bch:byt>    <dbl> <int> <dbl>
#> 1 reporter_step1 111.74ms 115.58ms     7.90    179.5KB     1.98     4     1
#> 2 reporter_step2    1.06s    1.06s     0.943      47MB     2.83     1     3
#> 3 knit_print    282.17ms 284.88ms     3.51     24.9MB     1.76     2     1
#> 4 officer        273.11ms 275.92ms     3.62     24.8MB     1.81     2     1
#> 5 knitr            2.25ms   2.65ms   344.      300.8KB     2.00   172     1

Rendering previewer

Rendering with override: (uncomment the option)

toHTML.data.frame <- function(x, ...) {
  shiny::tags$pre(
    shiny::HTML(
      #knitr::kable(x, format = "html")
      officer::to_html(flextable::flextable(x))
      # knitr::knit_print(flextable::flextable(x))
    )
  )
}

knitr::knit_print()

knitr::kable()

officer::to_html(flextable::flextable())

This might add a dependency and is the same as knitr::knit_print()