Leaflet not rendering in dynamically generated R markdown html knitr

Question

I\'ve created a R markdown report where the sections and tabsets are dynamically created.

I have an issue where the Leaflet maps are not being generated in the output

Answer 1

This is a similar problem as described here with Highcharter

Try:

---
title: "Test Leaflet Tabs"
output: html_document
---

`r knitr::opts_chunk$set(echo = FALSE, warning = FALSE, message = FALSE, cache = F)`

```{r setup, include=FALSE}
library(leaflet)
leaflet()
```

```{r,results='asis'}

filtered_list <- 1:3
cat("## Tabs {.tabset .tabset-fade .tabset-pills}", "\n")
for (estates in filtered_list){
    cat("###", estates, "\n")
    cat("\n\n\n")
    cat("This is where the map will go ")
    
# generate leaflet plot (doesn't even show white space if not stored in tagList)
    page <- htmltools::tagList(
         leaflet() %>%
            addTiles() %>%  # Add default OpenStreetMap map tiles
            addMarkers(lng=174.768, lat=-36.852, popup="The birthplace of R")
    )
    cat(as.character(page))
    }
```

Answer 2

I had a similar issue that was solved by putting the leaflet into a widget frame.

l <- leaflet() %>% 
  addTiles() %>% 
  addMarkers(map_data$Longitude, map_data$Latitude)

widgetframe::frameWidget(l, width = "100%")

This has the effect of saving html tiles for use in rendering. I'm pretty sure it just wraps the leaflet in a HMTL tag.