Include a javascript file in Shiny app

Question 1

What you need to do is:

create www folder in the same folder as server.R and ui.R
put javascript file into www folder.
put tags$head(tags$script(src="hoge.js")) in UI.

The folder looks like:

├── server.R
├── ui.R
└── www
    └── hoge.js

The ui.R is something like

library(shiny)
shinyUI(pageWithSidebar(
  headerPanel("New Application"),
  sidebarPanel(
    sliderInput("obs", 
                "Number of observations:", 
                min = 1, 
                max = 1000, 
                value = 500)
  ),
  mainPanel(
    plotOutput("distPlot"),
    tags$head(tags$script(src="hoge.js"))
  )
))

and server.R

library(shiny)
shinyServer(function(input, output) {
  output$distPlot <- renderPlot({
    dist <- rnorm(input$obs)
    hist(dist)
  })
})

Note that these are templates generated by Rstudio.

Now head of html looks like:

<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>
  ... snip ...
  <script src="shared/slider/js/jquery.slider.min.js"></script>
  <script src="hoge.js"></script>
</head>

Question 2

Another way is to use:

includeScript("mapManipulator.js"),

Question 3

 └──shiny
    ├── server.R
    ├── ui.R
    └── www
        ├── stylesheet.css
        └── js
             └── hoge.js

ui.R

Either one of them will work

1. tags$head(HTML("<script type='text/javascript' src='js/hoge.js'></script>"))

2. HTML('<head>
              <link rel="stylesheet" type="text/css" href="stylesheet.css">
              <script type="text/javascript" src="js/hoge.js"></script>
          </head>')

Question 4

My preferred way is like this:

ui.R:

    extendShinyjs(script = "app.js", functions = c("alerta")),

app.js:

shinyjs.alerta = function(text){
  alert(text);
}

server.R

  js$alerta("alerta alerta antifascista")

You can also include code like this:

ui.R after library imports:

jsCode <- "shinyjs.alerta = function(text){alert(text);}"

ui.R inside fluidPage:

extendShinyjs(text = jsCode, functions = c("alerta")),

the call from server.R would be the same

Question 5

Another option not discussed yet is that you just delete the ui.R file entirely, and then code the entire thing as a custom HTML file. Details here https://shiny.rstudio.com/articles/html-ui.html

In this article, the default HTML form elements are automatically used as inputs in server.R, but you can also build custom input (or output) elements for shiny with this guide https://shiny.rstudio.com/articles/building-inputs.html