Attempt to fix all player offline memory leak

Construct[BP]/scripts/classes/Instance/StructureInstance.js

@@ -3,7 +3,7 @@ import { StructureOutliner } from "../Render/StructureOutliner";
 import { StructureVerifier } from "../Verifier/StructureVerifier";
 import { Structure } from "../Structure/Structure";
 import { InstanceOptions } from "./InstanceOptions";
-import { TicksPerSecond } from "@minecraft/server";
+import { world, system, TicksPerSecond } from "@minecraft/server";
 import { InstanceNotPlacedError } from "../Errors/InstanceNotPlacedError";
 import { StructureMaterials } from "../Materials/StructureMaterials";
 import { VerificationRenderer } from "../Render/VerificationRenderer";
@@ -20,6 +20,7 @@ export class StructureInstance {
         this.structure = new Structure(structureId);
         this.options = new InstanceOptions(instanceName, structureId);
         this.refreshBox();
+        this.subscribeToEvents();
     }
 
     delete() {
@@ -50,6 +51,10 @@ export class StructureInstance {
         this.materials.refresh();
     }
 
+    subscribeToEvents() {
+        this.disableInstanceWhenNoPlayersOnline();
+    }
+
     getName() {
         return this.options.instanceName;
     }
@@ -240,6 +245,24 @@ export class StructureInstance {
             this.setLayer(this.options.currentLayer - 1);
     }
 
+    disableInstanceWhenNoPlayersOnline() {
+        // This prevents a memory leak when no players are online.
+        world.beforeEvents.playerLeave.subscribe(event => {
+            system.run(() => {
+                if (world.getAllPlayers().length === 0) {
+                    this.disable();
+                    this.shouldEnableOnJoin = true;
+                }
+            })
+        });
+        world.afterEvents.playerJoin.subscribe(event => {
+            if (this.shouldEnableOnJoin) {
+                this.enable();
+                this.shouldEnableOnJoin = false;
+            }
+        });
+    }
+
     toGlobalCoords(structureLocation) {
         return Vector.from(structureLocation).add(this.options.worldLocation);
     }