Moved filtered points to its own reactive element

dashboardShiny/app.R

@@ -45,7 +45,7 @@ ui <- bootstrapPage(
     id = "controls",  fixed = TRUE, draggable = FALSE, 
     top = 20, left = "auto", right = 20, bottom = "auto", width = 400, height = "auto",
     ### Date Picker
-    dateInput(inputId = "chosen_date_input",
+    dateInput(inputId = "date",
               label = h4("Select Date (only year and month)"),
               value = "2020-01-01", min = "2016-04-01", max = "2023-06-30",
               format = "yyyy-mm-dd", startview = "year"),
@@ -76,7 +76,7 @@ ui <- bootstrapPage(
 # Create Server Functionality ==================================================
 server <- function(input, output, session) {
   
-  ## Render leaflet basemap (with no markers)
+  ## 0. Render leaflet basemap -------------------------------------------------
   output$myMap <- renderLeaflet({
     leaflet(allPoints) %>% addTiles(group = "OSM") %>%
       addProviderTiles(providers$Stamen.TonerLite, group = "Toner Lite") %>%
@@ -88,47 +88,24 @@ server <- function(input, output, session) {
       fitBounds(~min(Longitude), ~min(Latitude), ~max(Longitude), ~max(Latitude))
   })
   
-  ## Initiate a 'reactiveValues' object
-  rctv <- shiny::reactiveValues()
-  
-  ## Start off with no date and no sensor selected
-  rctv$selected_sensor <- NULL
-  rctv$selected_date <- NULL
-  
-  ## When a date is selected...
-  shiny::observe({
-  
-    ### Require that a valid date has been selected
-    shiny::req(input$chosen_sensor_input != "")
-    rctv$selected_date <- ymd(input$chosen_date_input)
-    
-    ### Require that a valid sensor has been selected
-    shiny::req(input$chosen_sensor_input != "")
-    if (input$chosen_sensor_input == "Salinity") {
-      rctv$selected_sensor <- "SALT"
-    } 
-    else if ((input$chosen_sensor_input == "Temperature")) {
-      rctv$selected_sensor <- "TEMP"
-    }
-    
-    ### Capture the filtered data based upon the UI selection
-    rctv$filtered_data <- allData %>% 
-      dplyr::filter(Year == lubridate::year(rctv$selected_date),
-                    Month == lubridate::month(rctv$selected_date),
-                    Sensor == rctv$selected_sensor) %>% 
-      dplyr::collect()
-    
-    ### Extract points to plot from filtered data
-    rctv$filtered_points <- rctv$filtered_data %>% 
+  ## 1. Render points in map ---------------------------------------------------
+
+  ### Capture the filtered points to plot based upon the UI selection
+  filtered_points <- reactive({
+    allData %>% 
+      dplyr::filter(Year == lubridate::year(ymd(input$date)),
+                    Month == lubridate::month(ymd(input$date)),
+                    Sensor == input$sensor) %>% 
       dplyr::select(Station_ID, Stat_Name, Latitude, Longitude) %>% 
-      dplyr::distinct() %>% data.frame()
+      dplyr::distinct() %>% dplyr::collect() %>% data.frame()
   })
   
-  ## Plot filtered points on the map
+  ### Plot filtered points on the map
   observe({
-    leafletProxy(mapId = "myMap") %>%
-      addMarkers(data = rctv$filtered_points, lng = ~Longitude, lat = ~Latitude, 
-                 label = ~Station_ID, layerId = ~Station_ID, popup = ~Station_ID)  
+    leafletProxy(mapId = "myMap", data = filtered_points()) %>%
+      addMarkers(lng = ~Longitude, lat = ~Latitude, 
+                 label = ~Station_ID, layerId = ~Station_ID, 
+                 popup = ~Station_ID)  
   })
 
   # output$distPlot <- renderPlot({