Colors for factors in leaflet r

From: Manuel Sp?nola <mspinola10 at gmail.com>
To: "r-sig-geo at r-project.org" <r-sig-geo at r-project.org>
Subject: [R-sig-Geo] Colors for factors in leaflet r

I am trying to add a legend to a leaflet map but I got the following error

data(meuse)
coordinates(meuse) <- ~x+y
proj4string(meuse) <- CRS("+init=epsg:28992")
WGS84 <- CRS("+proj=longlat +ellps=WGS84")
meuse <- spTransform(meuse, WGS84)

pal <- colorFactor(palette = c("red", "blue", "green"), levels =
meuse$soil)
meuse$soil
leaflet(meuse) %>%
  addTiles() %>%
  addCircleMarkers(stroke = FALSE, fillOpacity = 1) %>%
  addLegend("topright", color = ~pal(soil), labels=c("Type 1", "Type 2",
"Type 3"), title="Soil type")