Can tufte_html format be split into chapters in bookdown/rmarkdown?

Is it possible to split a tufte_html document from the R tufte package into one file per chapter? I'd like to write a whole book. Bookdown lets me organize the chapters in their own files, and the chapters start new pages in the pdf output, but for the html output, it's just one file.

Here's what I tried that does not work.

index.Rmd

---
title: "Probability and Statistics<br />"
author: "Bob Carpenter"
date: "2018"
output:
  tufte::tufte_html
---

```{r setup, include=FALSE}
bookdown::tufte_html_book(split_by = "chapter")
```

# A Chapter

Blah blah blah.

# Another Chapter

Blah blah blah.
```

_bookdown.yml

rmd_files: [
  "index.Rmd",
  "another_file.Rmd"
]

another_file.Rmd

# Yet another chapter

Foo bar baz.



$ R
> library(bookdown)
> render_book("index.Rmd")

This produces a single html document as output, not one file per chapter. I also tried replacing the split_by call with bookdown::tufte_html_book(split_by = "chapter").

Here's my sessionInfo()

> sessionInfo()
R version 3.5.0 (2018-04-23)
Platform: x86_64-apple-darwin15.6.0 (64-bit)
Running under: macOS High Sierra 10.13.6

Matrix products: default
BLAS: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRblas.0.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/3.5/Resources/lib/libRlapack.dylib

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] bookdown_0.7

loaded via a namespace (and not attached):
 [1] Rcpp_0.12.18    tufte_0.4       digest_0.6.15   rprojroot_1.3-2
 [5] backports_1.1.2 magrittr_1.5    evaluate_0.10.1 stringi_1.2.2  
 [9] rstudioapi_0.7  rmarkdown_1.10  tools_3.5.0     stringr_1.3.1  
[13] xfun_0.1        yaml_2.2.0      compiler_3.5.0  htmltools_0.3.6
[17] knitr_1.20

Solution

I don't quite understand what you were trying to do in the setup chunk in index.Rmd, but that is not the correct way to specify output formats in R Markdown. Here is the working example:

index.Rmd:

---
title: "Probability and Statistics<br />"
author: "Bob Carpenter"
date: "2018"
output:
  bookdown::tufte_html_book:
    split_by: chapter
---

# A Chapter

Blah blah blah.

# Another Chapter

Blah blah blah.

another_file.Rmd:

# Yet another chapter

Foo bar baz.

To render the book:

bookdown::render_book('index.Rmd')