From 0bfc918c7aae47597b0e5d55672e00ebaf60ae65 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Karel=20Kl=C3=ADma?= <karelklima@gmail.com>
Date: Wed, 6 Aug 2025 10:49:31 +0200
Subject: [PATCH] Re-added filtering of duplicate quads

---
 library/options.ts |  1 -
 library/rdf.ts     | 11 +++++++++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/library/options.ts b/library/options.ts
index 7aec8ce..7c453c7 100644
--- a/library/options.ts
+++ b/library/options.ts
@@ -24,7 +24,6 @@ const defaultOptions = {
   engine: new QueryEngine(),
   take: 1000,
   logQuery: () => {},
-  distinctConstruct: true, // Needed for Comunica to filter duplicate quads on CONSTRUCT queries
 };
 
 let globalOptions: Options = {};
diff --git a/library/rdf.ts b/library/rdf.ts
index 0311b36..ac03d24 100644
--- a/library/rdf.ts
+++ b/library/rdf.ts
@@ -4,6 +4,8 @@ export type { RDF };
 
 export { fromRdf, toRdf } from "npm:rdf-literal@^2";
 
+import { quadToStringQuad } from "npm:rdf-string@^2";
+
 import { DataFactory, DefaultGraph } from "npm:rdf-data-factory@^2";
 export { DataFactory, DefaultGraph };
 
@@ -19,8 +21,17 @@ export type Graph = Map<IRI, Node>;
 export const quadsToGraph = (quadStream: RDF.ResultStream<RDF.Quad>) => {
   return new Promise<Graph>((resolve, reject) => {
     const graph: Graph = new Map();
+    const included: Record<string, true> = {};
 
     quadStream.on("data", (quad) => {
+      const hash = Object.values(quadToStringQuad(quad)).join(" ");
+
+      if (included[hash]) {
+        return;
+      }
+
+      included[hash] = true;
+
       const s = quad.subject.value;
       const p = quad.predicate.value;