Leaflet geolocate test

README.md

test of Leaflet

WheresWally.R

# ==== libraries
library(shiny)
library(leaflet)
library(shinyjs)
 
# ==== fonction allowing geolocalisation
jsCode <- '
shinyjs.geoloc = function() {
    navigator.geolocation.getCurrentPosition(onSuccess, onError);
    function onError (err) {
        Shiny.onInputChange("geolocation", false);
    }
    function onSuccess (position) {
        setTimeout(function () {
            var coords = position.coords;
            console.log(coords.latitude + ", " + coords.longitude);
            Shiny.onInputChange("geolocation", true);
            Shiny.onInputChange("lat", coords.latitude);
            Shiny.onInputChange("long", coords.longitude);
        }, 5)
    }
};
'
 
 
# ==== server
server <- function(input, output) {
 
    # Basic map 
    output$map <- renderLeaflet({
        leaflet() %>% 
          setView(lng=0, lat=0, zoom=2 ) %>%
        addProviderTiles("Esri.WorldImagery")
    })
    
    # Find geolocalisation coordinates when user clicks
    observeEvent(input$geoloc, {
        js$geoloc()
    })
 
 
    # zoom on the corresponding area
    observe({
        if(!is.null(input$lat)){
            map <- leafletProxy("map")
            dist <- 0.2
            lat <- input$lat
            lng <- input$long
            map %>% fitBounds(lng - dist, lat - dist, lng + dist, lat + dist)
        }
     })
}
 
 
 
# ==== UI
ui <- fluidPage(
    
    # Tell shiny we will use some Javascript
    useShinyjs(),
    extendShinyjs(text = jsCode),
 
    # One button and one map
    br(),
    actionButton("geoloc", "Localize me", class="btn btn-primary", onClick="shinyjs.geoloc()"),
    leafletOutput("map", height="600px")
)
 
shinyApp(ui = ui, server = server)