Example of dygraph with percent formatted y axis.

dygraph_with_percents.R

#
# This is a Shiny web application. You can run the application by clicking
# the 'Run App' button above.
#
# Find out more about building applications with Shiny here:
#
#    http://shiny.rstudio.com/
#

library(shiny)
library(dygraphs)
library(xts)

data <- xts(c(0.1, 0.523, 0.231, 0.78), as.Date("2017-01-01") + 0:3)

# Define UI for application that draws a dygraph
ui <- fluidPage(
   
   # Application title
   titlePanel("Test Dygraph"),
   
   # Show a plot of the generated dygraph
   mainPanel(
     dygraphOutput("testPlot")
  )
)

# Define server logic required to draw a dygraph
server <- function(input, output) {
   
   output$testPlot <- renderDygraph({
     res <- dygraph(data) %>%
       dyAxis("y",
              valueFormatter = "function(v){return (v*100).toFixed(1) + '%'}",
              axisLabelFormatter = "function(v){return (v*100).toFixed(0) + '%'}")
     
     res
   })
}

# Run the application 
shinyApp(ui = ui, server = server)