prevent undefined/null values breaking graphs or scales

lib/servers.js

@@ -45,6 +45,10 @@ class ServerRegistration {
   getUpdate (timestamp, resp, err, version) {
     const update = {}
 
+    // Always append a playerCount value
+    // When resp is undefined (due to an error), playerCount will be null
+    update.playerCount = getPlayerCountOrNull(resp)
+
     if (resp) {
       if (resp.version && this.updateProtocolVersionCompat(resp.version, version.protocolId, version.protocolIndex)) {
         // Append an updated version listing
@@ -65,10 +69,6 @@ class ServerRegistration {
         update.favicon = this.getFaviconUrl()
       }
 
-      // Append a result object
-      // This filters out unwanted data from resp
-      update.playerCount = resp.players.online
-
       if (config.logToDatabase) {
         // Update calculated graph peak regardless if the graph is being updated
         // This can cause a (harmless) desync between live and stored data, but it allows it to be more accurate for long surviving processes