update js reference and comparison

generate-reference-triangles/index.js

diff --git a/generate-reference-triangles/index.js b/generate-reference-triangles/index.js
index 11724f9..9356209 100755
--- a/generate-reference-triangles/index.js
+++ b/generate-reference-triangles/index.js
@@ -26,6 +26,9 @@
 console.log('miliseconds =', end - start);
 console.log('triangles =', delaunator.triangles.length);
 
-const trianglesAr = Array.from(delaunator.triangles);
-writeFileSync(outputFile, JSON.stringify(trianglesAr));
+if (outputFile) {
+    console.log('Saving to', outputFile)
+    const trianglesAr = Array.from(delaunator.triangles);
+    writeFileSync(outputFile, JSON.stringify(trianglesAr));
+}