custom color palette for leaflet R consistently throws a warning

Question

I create a leaflet app. For one particular value within my data, I want to use a custom color. For the remaining colors, I want to use a ramp. As I don't know any better, I create a simple color function with an ifelse-statement.

Here is sample-code:

library(leaflet)

colors <- function(x){
  return(ifelse(x==1422, #if it was founded in 1422
                "#ff7400", #return this orange, else use colorNumeric
                colorNumeric(palette="viridis",
                             domain=unique(breweries91$founded) %>% setdiff(1422), 
                             na.color=NA)(x)
                )
    )
  }


breweries91 %>% leaflet() %>% addTiles() %>% addCircleMarkers(fillColor =~colors(founded),
                                                              weight=0,
                                                              fillOpacity = 1)

the result looks as expected, with one point in orange.

But it throws the following warning, as if the Brewery from 1422 still passes through colorNumeric()

Warning message:
In colorNumeric(palette = "viridis", domain = unique(breweries91$founded) %>%  :
  Some values were outside the color scale and will be treated as NA

Answer 1

One possibility, that better handles missing values, would be:

colors <- function(x){
  return(if_else(x==1422, #if it was founded in 1422
                "#ff7400", #return this orange, else use colorNumeric
                suppressWarnings(colorNumeric(palette="viridis",
                             domain=unique(breweries91$founded) %>% setdiff(1422), 
                             na.color="black")(x)),
                missing = "#FF000000"
                )
    )
  }

as indicated here: ifelse shows warning based on the else function even when the test condition is met

Answer 2

@Beni pointed out the important element about the ifelse test. I am sharing my solution and reproductible example, where the specific value is remplaced by NA beforehand. I used meuse from sp, transormed it to sf. The copper is equivalent to founded and the value 14 is the equivalent of the specified 1422

Edit: It has been specified that the datset contain NA. I also put an argument orange_value for the 14 / 1422 value.

library(leaflet)
library(sf)
library(dplyr)

data(meuse, package = "sp") 
meuse_sf = st_as_sf(meuse, coords = c("x", "y"), crs = 28992) %>% 
  st_transform(crs=4326)

# Adding some missing values to be displayed black
meuse_sf[c(1:3) , "copper"] = NA

colors <- function(x,orange_value){
  # Temporary change of "minimum" highlighted value
  x2 = x %>%  na_if(orange_value)
  
  # General color palette
  x3=colorNumeric(palette="viridis",
                  domain = range(x2, na.rm=TRUE),
                  na.color="black")(x2)
  
  #Re-specifying the orange value 
  x3[x==orange_value] = "#ff7400"
  return(x3)
  
}

meuse_sf %>%
  leaflet() %>% addTiles() %>% addCircleMarkers(fillColor =~colors(copper,14),
                                                weight=0,
                                                fillOpacity = 1)