cleaned up viewers

build_vtk_bundle/node_modules/d3-array/src/difference.js

@@ -0,0 +1,11 @@
+import {InternSet} from "internmap";
+
+export default function difference(values, ...others) {
+  values = new InternSet(values);
+  for (const other of others) {
+    for (const value of other) {
+      values.delete(value);
+    }
+  }
+  return values;
+}