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Register a Custom Render Backend

Source: R/render.R
fr_register_backend.Rd

Registers a new output format backend so that fr_render() can produce output in that format. Third-party packages can use this to add HTML, DOCX, or other formats without modifying arframe source.

Usage

fr_register_backend(format, extensions, render_fn, description = "")

Arguments

format

Character scalar. Format identifier (e.g., "html").

extensions

Character vector. File extensions that map to this format (e.g., c("html", "htm")).

render_fn

Function. The render function with signature function(spec, page_groups, col_panels, path).

description

Character scalar. Human-readable description.

Value

Invisibly returns NULL.

See also

fr_backends() to list registered backends, fr_render().

Examples

# Register a custom CSV backend
fr_register_backend(
  format = "csv",
  extensions = "csv",
  render_fn = function(spec, page_groups, col_panels, path) {
    utils::write.csv(spec$data, path, row.names = FALSE)
  },
  description = "CSV export (data only)"
)

# Verify it appears in the backend list
fr_backends()
#>   format extensions                   description
#> 1    rtf   rtf, doc              Rich Text Format
#> 2  latex        tex     LaTeX source (tabularray)
#> 3    pdf        pdf               PDF via XeLaTeX
#> 4   html  html, htm HTML preview (self-contained)
#> 5    csv        csv        CSV export (data only)

# Use the custom backend
out <- file.path(tempdir(), "demo.csv")
tbl_demog |> fr_table() |> fr_render(out)
readLines(out, n = 3)
#> [1] "\"characteristic\",\"placebo\",\"zom_50mg\",\"zom_100mg\",\"total\",\"group\""
#> [2] "\"Subjects, n\",\"45\",\"45\",\"45\",\"135\",\"n\""                           
#> [3] "\"Age (years)\",\"\",\"\",\"\",\"\",\"age_cont\""                             
unlink(out)
fr_unregister_backend("csv")