a.r

library(sf)

## Linking to GEOS 3.5.1, GDAL 2.1.2, proj.4 4.9.3

library(leaflet.extras)

## Loading required package: leaflet

P_crs <- st_crs("+proj=aea +datum=WGS84")

tjson <- readLines("https://gist.githubusercontent.com/jasondavies/4188334/raw/c5b150aac00bbb67c08593304848c2f5fcaa04db/readme-world.json")

## Warning in readLines("https://gist.githubusercontent.com/jasondavies/
## 4188334/raw/c5b150aac00bbb67c08593304848c2f5fcaa04db/readme-world.json"):
## incomplete final line found on 'https://gist.githubusercontent.com/
## jasondavies/4188334/raw/c5b150aac00bbb67c08593304848c2f5fcaa04db/readme-
## world.json'

resolutions <- c(8192, 4096, 2048, 1024, 512, 256)

crs<-  leafletCRS(
  crsClass = 'L.Proj.CRS',
  code = '',
  proj4def = P_crs$proj4string, 
  resolutions = resolutions)



leaflet(options= leafletOptions(
  crs=crs)) %>%
  addGeoJSONv2(tjson)