prevent undefined/null values breaking graphs or scales

assets/js/scale.js

@@ -26,7 +26,7 @@ export class RelativeScale {
   }
 
   static scaleMatrix (data, tickCount, maxFactor) {
-    const max = Math.max(...data.flat())
+    const max = Math.max(...data.flat().filter(val => val !== null))
 
     return RelativeScale.scale([0, RelativeScale.isFiniteOrZero(max)], tickCount, maxFactor)
   }
@@ -46,8 +46,8 @@ export class RelativeScale {
         max: 0
       }
     } else {
-      const min = Math.min(...data)
-      const max = Math.max(...data)
+      const min = Math.min(...data.filter(val => val !== null))
+      const max = Math.max(...data.filter(val => val !== null))
 
       return {
         min: RelativeScale.isFiniteOrZero(min),

docs/CHANGELOG.md

@@ -1,3 +1,8 @@
+**5.5.2** *(June 12 2020)*
+- Fixed ping errors causing server graphs (or the historical graph) to sometimes disappear.
+- Fixed ping errors causing server graphs to reset their Y scale minimum to 0.
+- Improved zoomed detection and updating of the historical graph with recommendations by [@leeoniya](https://github.com/leeoniya).
+
 **5.5.1** *(June 10 2020)*
 - New tooltip hover design on the historical graph. It will highlight the server closest to your cursor.
 - Historical graph is now limited to 10,000 increments on the Y axis. This prevents servers with over 100,000 players forcing the graph into 100,000 increments.

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