Fix undefined check

assets/index.html

@@ -231,6 +231,7 @@
                 });
 
                 transformedVerts.forEach(v => {
+                    if (!v) return;
                     const proj = v.project();
                     if (!proj) return;
                     ctx.beginPath();
@@ -240,8 +241,11 @@
                 });
 
                 for (let i = 0; i < transformedVerts.length - 1; i++) {
-                    const p1 = transformedVerts[i].project();
+                    const v1 = transformedVerts[i];
-                    const p2 = transformedVerts[i + 1].project();
+                    const v2 = transformedVerts[i + 1];
+                    if (!v1 || !v2) continue;
+                    const p1 = v1.project();
+                    const p2 = v2.project();
                     if (!p1 || !p2) continue;
                     ctx.beginPath();
                     ctx.moveTo(p1.x, p1.y);