Shiny update choices of selectizeInput based on radio buttons

Question

I am trying to update the choices in a selectizeInput() based on whether the user clicks "Common name" or "Scientific name" buttons. The default is "Common name".

I am aware of conditionalPanel() from this answer, but my choices will link to an output plot so I need them to be reactive. Therefore, upon clicking "Scientific name", I want the current choices to be cleared and then only the new choices (names_vector2) are available to be selected. Similarly, if the user then clicks back to "Common name" I want the current choices cleared and only choices from names_vector1 to be available for selection.

Hope that makes sense!

library(shiny)
library(shinyWidgets)

names_vector1 = paste0("common", 1:10)
names_vector2 = paste0("scientific", 1:10)

ui = fluidPage(
  fluidRow(
    selectizeInput(
      inputId = "species_selector",
      label = "Choose a species:",
      selected = "common1",
      choices = c("Choose" = "", names_vector1),
      options = list(
        maxOptions = 5,
        maxItems = 4
      )
    ),
    awesomeRadio(
      inputId = "species_selector_type",
      label = NULL,
      choices = c("Common name","Scientific name"),
      selected = "Common name",
      inline = TRUE
    )
  )
)

server = server = server = function(input, output, session){
 
  # I want to change the selectizeInput choices as the user clicks the buttons:
  # "Common name" and "Scientific name"
  observeEvent(input$species_selector_type {
    
    if (input$species_selector_type == "Scientific name")
    updateSelectizeInput(
      session,
      inputId = "species_selection",
      choices = c("Choose" = "", names_vectors),
    )
  })
  # The desired result is to:
  # 1. Clear the current selectiveInput selected names each time a new button is clicked
  # 2. Update the choices so that:
        # Common name = names_vector1
        # Scientific name = names_vector2
}

shinyApp(ui, server)

Answer 1

You were almost there - added an else if statement:

library(shiny)
library(shinyWidgets)

names_vector1 = paste0("common", 1:10)
names_vector2 = paste0("scientific", 1:10)

ui = fluidPage(fluidRow(
  selectizeInput(
    inputId = "species_selector",
    label = "Choose a species:",
    selected = "common1",
    choices = c("Choose" = "", names_vector1),
    options = list(maxOptions = 5,
                   maxItems = 4)
  ),
  awesomeRadio(
    inputId = "species_selector_type",
    label = NULL,
    choices = c("Common name", "Scientific name"),
    selected = "Common name",
    inline = TRUE
  )
))

server = server = server = function(input, output, session) {
  observeEvent(input$species_selector_type, {
    if (input$species_selector_type == "Common name") {
      updateSelectizeInput(session,
                           inputId = "species_selector",
                           choices = c("Choose" = "", names_vector1))
    } else if (input$species_selector_type == "Scientific name") {
      updateSelectizeInput(session,
                           inputId = "species_selector",
                           choices = c("Choose" = "", names_vector2))
    }
  })
}

shinyApp(ui, server)