Capture map calls before map has been rendered

[schloerke]

Allow extra leaflet proxy methods while the map is hidden with outputOptions(output, "map", suspendWhenHidden = FALSE)

Fixes #659

Reprex:

library(shiny)
library(leaflet)
library(raster)

ui <- navbarPage("leafletProxy demo",
                 id = "active_tab",
                #  selected = "Map",
   tabPanel("Data",
            actionButton("add_raster", "Upload raster layer"),
            leafletOutput("localMap")
            ),
    tabPanel("Map",
             leafletOutput("hiddenMap"))
   )


server <- function(input, output) {

    # updateNavbarPage(inputId = "active_tab", selected = "Data")

    RV <- reactiveValues(overlay = NULL)

    ## Large (many-celled) raster to be added via leafletProxy()
    observeEvent(input$add_raster, {
        r <- raster(matrix(1:14e4, 350, 400, byrow = TRUE),
                    xmn = -120, xmx = -110, ymn = 40, ymx = 50,
                    crs = CRS("+init=epsg:4326"))
        RV$overlay <- r
    })

    ## Base map
    output$localMap <- renderLeaflet({
        message("rendering local map")
        leaflet() %>%
            addTiles() %>%
            fitBounds(lng1 = -120, lng2 = -100, lat1 = 30, lat2 = 50)
    })
    output$hiddenMap <- renderLeaflet({
        message("rendering hidden map")
        leaflet() %>%
            addTiles() %>%
            fitBounds(lng1 = -120, lng2 = -100, lat1 = 30, lat2 = 50)
    })

    ## ## Uncomment this block to confirm that setting `suspendWhenHidden=FALSE`
    ## ## does not actually work as hoped.
    outputOptions(output, "hiddenMap", suspendWhenHidden = FALSE)

    ## Dynamically updated map element
    observeEvent(RV$overlay, {
        message("Adding raster layer")
        leafletProxy("localMap") %>%
            addRasterImage(RV$overlay, colors = "Spectral", opacity = 0.4)
        leafletProxy("hiddenMap") %>%
            addRasterImage(RV$overlay, colors = "Spectral", opacity = 0.4)
    })
}

shinyApp(ui, server)

• Click "add raster"
• Click "Map"
• Rainbow raster should appear in Map panel

PR:

rstudio/leaflet@main behavior: (No rainbow on Map panel)

---

PR task list:

• Update NEWS
• Add tests (where appropriate)
  • R code tests: tests/testthat/
  • Visual tests: R/zzz_viztest.R
• Update documentation with devtools::document()

[schloerke]

Failing tests are independent of this PR. Merging