Merge pull request #2125 from PR0M3TH3AN/perf/optimize-feed-engine-normalization-10953414898380924451

⚡ Optimize Feed Engine Normalization Loop

benchmarks/feed_engine_bench.js

@@ -0,0 +1,76 @@
+
+import { createFeedEngine } from "../js/feedEngine/index.js";
+import { performance } from "perf_hooks";
+
+// Mock logger
+const logger = {
+  log: () => {},
+  warn: () => {},
+  error: () => {},
+};
+
+// Polyfill localStorage to silence errors
+if (typeof globalThis.localStorage === "undefined") {
+  globalThis.localStorage = {
+    getItem: () => null,
+    setItem: () => {},
+    removeItem: () => {},
+  };
+}
+
+async function runBenchmark() {
+  const engine = createFeedEngine({ logger });
+  const feedName = "bench-feed";
+
+  // Create items
+  const itemCount = 100000;
+  const items = [];
+  for (let i = 0; i < itemCount; i++) {
+    items.push({
+      video: { id: `v${i}`, created_at: Date.now() },
+      metadata: { some: "data" },
+    });
+  }
+
+  // Define stages
+  const stages = [];
+
+  // 10 stages that return null (no change) - STRICT PASS THROUGH
+  for (let i = 0; i < 10; i++) {
+    stages.push(async (items) => {
+      return null;
+    });
+  }
+
+  // 10 stages that return the same items array (identity) - STRICT PASS THROUGH
+  for (let i = 0; i < 10; i++) {
+    stages.push(async (items) => {
+      return items;
+    });
+  }
+
+  engine.registerFeed(feedName, {
+    source: async () => [...items],
+    stages: stages,
+  });
+
+  console.log(`Starting benchmark with ${itemCount} items and ${stages.length} stages...`);
+
+  const iterations = 50;
+  const start = performance.now();
+
+  for (let i = 0; i < iterations; i++) {
+    await engine.runFeed(feedName);
+    if (i % 5 === 0) process.stdout.write(".");
+  }
+
+  const end = performance.now();
+  const totalTime = end - start;
+  const avgTime = totalTime / iterations;
+
+  console.log("\n");
+  console.log(`Total time: ${totalTime.toFixed(2)}ms`);
+  console.log(`Average time per run: ${avgTime.toFixed(2)}ms`);
+}
+
+runBenchmark().catch(console.error);

js/feedEngine/engine.js

@@ -205,10 +205,8 @@ export function createFeedEngine({ logger } = {}) {
 
     for (const stage of entry.stages) {
       const result = await stage(items, context);
-      if (Array.isArray(result)) {
+      if (Array.isArray(result) && result !== items) {
         items = normalizeItems(result);
-      } else if (result == null) {
-        items = normalizeItems(items);
       }
     }