From 03bf0eae77a419170128fd9975b171757f345b07 Mon Sep 17 00:00:00 2001
From: Stewart Allen <stewart.allen@gmail.com>
Date: Thu, 12 Jan 2023 00:28:21 -0500
Subject: [PATCH] re-enable ref cleaning with changes

---
 src/geo/slicer.js | 23 +++++++++++++++--------
 1 file changed, 15 insertions(+), 8 deletions(-)

diff --git a/src/geo/slicer.js b/src/geo/slicer.js
index ac509546..fa099c2c 100644
--- a/src/geo/slicer.js
+++ b/src/geo/slicer.js
@@ -405,20 +405,27 @@ async function sliceZ(z, points, options = {}) {
     }
 
     // free objects to be re-claimed and reduce memory pressure
-    if (false) {
+    if (true) {
         delete rval.groups
         delete rval.lines
-        delete rval.clip.m_AllPolys
 
+        if (rval.tops)
         for (let top of rval.tops) {
-            top.poly.freeParentRefs();
-            top.simple.freeParentRefs();
-            for (let shell of top.shells) shell.freeParentRefs();
-            for (let fillo of top.fill_off) fillo.freeParentRefs();
-            for (let last of top.last) last.freeParentRefs();
+            if (top.poly) {
+                top.poly.freeParentRefs();
+                top.simple.freeParentRefs();
+                for (let shell of top.shells) shell.freeParentRefs();
+                for (let fillo of top.fill_off) fillo.freeParentRefs();
+                for (let last of top.last) last.freeParentRefs();
+            } else {
+                top.freeParentRefs();
+            }
         }
 
-        for (let clip of rval.clip) clip.freeParentRefs();
+        if (rval.clip) {
+            for (let clip of rval.clip) clip.freeParentRefs();
+            if (rval.clip.m_AllPolys) delete rval.clip.m_AllPolys
+        }
     }
 
     if (each) each(rval);