The goal of keys is to add hotkeys to shiny applications using Mousetrap. With keys, you can:

Assign hotkeys on app load
Add and remove hotkeys from server
Pause and unpause hotkeys from server
Record keys from server

Installation

Install the released version of keys from CRAN:

install.packages("keys")

Or install the development version from GitHub with:

# install.packages("devtools")
devtools::install_github("r4fun/keys")

You can also install keys with conda-forge. More information here: https://github.com/conda-forge/r-keys-feedstock

Usage

To use keys, start by adding a dependency to it using useKeys().

Then, you can add a keysInput to the UI:

library(shiny)
library(keys)
hotkeys <- c(
  "1",
  "command+shift+k",
  "up up down down left right left right b a enter"
)
ui <- fluidPage(
  useKeys(),
  keysInput("keys", hotkeys)
)
server <- function(input, output, session) {
  observeEvent(input$keys, {
    print(input$keys)
  })
}
shinyApp(ui, server)

You can add binding after application launch using addKeys.

library(shiny)
library(keys)
ui <- fluidPage(
  useKeys(),
  actionButton("add", "Add keybinding")
)
server <- function(input, output, session) {
  observeEvent(input$add, {
    addKeys("keys", c("a", "b", "c"))
  })
  observeEvent(input$keys, {
    print(input$keys)
  })
}
shinyApp(ui, server)

Bindings can be removed after application launch using removeKey.

library(shiny)
library(keys)
ui <- fluidPage(
  useKeys(),
  keysInput("keys", c("a", "b", "c")),
  actionButton("rm", "Remove `a` keybinding")
)
server <- function(input, output, session) {
  observeEvent(input$rm, {
    removeKeys("a")
  })
  observeEvent(input$keys, {
    print(input$keys)
  })
}
shinyApp(ui, server)

For more information about what types of hotkeys you can use, please take a look at the mousetrap github repository.

Acknowledgements

All credit goes to Craig Campbell who is the author of Mousetrap.