Demo shiny Rmd with topojson file

test_shiny.Rmd

---
title: "Test RMD"
output: html_document
runtime: shiny
---

```{r setup, include=FALSE}
knitr::opts_chunk$set(echo = TRUE)
library(tidyverse)
library(leaflet)
library(shiny)
library(geojsonio)
library(sp)
```

## GeoJSON

```{r geo}
us <- geojsonio::geojson_read("http://eric.clst.org/wupl/Stuff/gz_2010_us_040_00_500k.json", what = "sp")
leaflet(us) %>% addTiles() %>%  addPolygons()
```



## TopoJSON
```{r topo}
eu <- geojsonio::geojson_read("https://raw.githubusercontent.com/Leaflet/Leaflet.VectorGrid/master/docs/eu-countries.topo.json", what = "sp")
leaflet(eu) %>% addTiles() %>%  addPolygons()
```