From 71368511236d592cb98baa0a4ac2ce33db61793e Mon Sep 17 00:00:00 2001
From: Nick Krecklow <hello@github.nklow.com>
Date: Mon, 11 May 2020 18:16:41 -0500
Subject: [PATCH] centralize shift behavior into TimeTracker func

---
 lib/servers.js | 14 ++------------
 lib/time.js    | 20 ++++++++++----------
 2 files changed, 12 insertions(+), 22 deletions(-)

diff --git a/lib/servers.js b/lib/servers.js
index 412983e..58e6b8d 100644
--- a/lib/servers.js
+++ b/lib/servers.js
@@ -26,23 +26,13 @@ class ServerRegistration {
     const playerCount = resp ? resp.players.online : null
 
     // Store into in-memory ping data
-    this._pingHistory.push(playerCount)
-
-    // Trim pingHistory to avoid memory leaks
-    if (this._pingHistory.length > TimeTracker.getMaxServerGraphDataLength()) {
-      this._pingHistory.shift()
-    }
+    TimeTracker.pushAndShift(this._pingHistory, playerCount, TimeTracker.getMaxServerGraphDataLength())
 
     // Only notify the frontend to append to the historical graph
     // if both the graphing behavior is enabled and the backend agrees
     // that the ping is eligible for addition
     if (updateHistoryGraph) {
-      this.graphData.push(playerCount)
-
-      // Trim old graphPoints according to #getMaxGraphDataLength
-      if (this.graphData.length > TimeTracker.getMaxGraphDataLength()) {
-        this.graphData.shift()
-      }
+      TimeTracker.pushAndShift(this.graphData, playerCount, TimeTracker.getMaxGraphDataLength())
     }
 
     // Delegate out update payload generation
diff --git a/lib/time.js b/lib/time.js
index 1710644..34c8afd 100644
--- a/lib/time.js
+++ b/lib/time.js
@@ -10,11 +10,7 @@ class TimeTracker {
   newPingTimestamp () {
     const timestamp = new Date().getTime()
 
-    this._points.push(timestamp)
-
-    if (this._points.length > TimeTracker.getMaxServerGraphDataLength()) {
-      this._points.shift()
-    }
+    TimeTracker.pushAndShift(this._points, timestamp, TimeTracker.getMaxServerGraphDataLength())
 
     // Flag each group as history graph additions each minute
     // This is sent to the frontend for graph updates
@@ -24,11 +20,7 @@ class TimeTracker {
       this._lastHistoryGraphUpdate = timestamp
 
       // Push into timestamps array to update backend state
-      this._historicalTimestamps.push(timestamp)
-
-      if (this._historicalTimestamps.length > TimeTracker.getMaxGraphDataLength()) {
-        this._historicalTimestamps.shift()
-      }
+      TimeTracker.pushAndShift(this._historicalTimestamps, timestamp, TimeTracker.getMaxGraphDataLength())
     }
 
     return {
@@ -60,6 +52,14 @@ class TimeTracker {
   static getMaxGraphDataLength () {
     return Math.ceil(config.graphDuration / config.rates.pingAll)
   }
+
+  static pushAndShift (array, value, maxLength) {
+    array.push(value)
+
+    if (array.length > maxLength) {
+      array.shift()
+    }
+  }
 }
 
 module.exports = TimeTracker