This is an R package for creating htmlwidgets that are html mustache templates populated with data.

If you are making a one-off web page, it is better to just build the page than to use this tool. But if you making several versions of a static web page with each having the same layout but being populated with different data, then this can be a good tool to use. This package was developed particularly for use with Trelliscope, where often we want to design panels that are composed of custom html content.

You can learn more about mustache templates here.

You can install the development version of mustachewidget with the following:

remotes::install_github("hafen/mustachewidget")

Here are a few examples of how to use the package.

library(mustachewidget)

mustache("Hi, {{name}}", data = list(name = "Bob"))

This will output an htmlwidget web page that says "Hi, Bob".

mustache("
  Hello, {{name.first}} <b>{{name.last}}</b>!
  ",
  data = list(name = list(first = "Bob", last = "Smith"))
)

mustache("
  <h1>Alphabet</h1>
  <ul>
    {{#values}}
    <li>{{.}}</li>
    {{/values}}
  </ul>
  ",
  data = list(values = letters)
)

mustache("
  <h1>{{title}}</h1>
  {{#show}}
    <p>{{content}}</p>
  {{/show}}
  {{^show}}
    (no content)
  {{/show}}
  ",
  data = list(title = "My Title", show = TRUE, content = "My Content")
)

If you want to include a locally-created plot in an mustachewidget output, this package has a utility function particularly for ggplot2, ggsave_base64(), that will save a plot as a base64 encoded string.

library(ggplot2)
p <- ggplot(mtcars, aes(x = wt, y = mpg)) + geom_point()
p64 <- ggsave_base64(p)

mustache("
  <h1>My plot</h1>
  <img width='500' src='{{plot}}' />
  ",
  data = list(plot = p64)
)

Instead of specifying the template as a string, you can also specify a file path to a template html file.

Also, you may have CSS or JavaScript dependencies that you want to include in the output. You can specify these as well.

asset_dir <- system.file("example", package = "mustachewidget")

mustache(
  file.path(asset_dir, "template.html"),
  list(name = "Bob"),
  dependencies = htmltools::htmlDependency(
    name = "template",
    version = "1",
    src = c(file = asset_dir),
    script = "template.js",
    stylesheet = "template.css"
  )
)