⚡ Bolt: [performance improvement] Replace getEdges() with memory-efficient iterators in hot loops

packages/core/src/graph/graph.ts

@@ -165,6 +165,17 @@ export class Graph {
     });
   }
 
+  /**
+   * Memory-efficient iteration over all edges without allocating intermediate arrays.
+   * Useful in high-frequency hot loops.
+   */
+  forEachEdge(callback: (source: string, target: string, weight: number) => void): void {
+    for (const [key, weight] of this.edges) {
+      const { source, target } = Graph.parseEdgeKey(key);
+      callback(source, target, weight);
+    }
+  }
+
   toJSON() {
     return {
       nodes: this.getNodes(),

packages/core/src/graph/hits.ts

@@ -48,19 +48,18 @@ export class HITSService {
         const incoming: { sourceIndex: number, weight: number }[][] = new Array(N).fill(null).map(() => []);
         const outgoing: { targetIndex: number, weight: number }[][] = new Array(N).fill(null).map(() => []);
 
-        const allEdges = graph.getEdges();
-        for (const edge of allEdges) {
-            if (edge.source === edge.target) continue;
+        graph.forEachEdge((source, target, weight) => {
+            if (source === target) return;
 
-            const sourceIndex = urlToIndex.get(edge.source);
-            const targetIndex = urlToIndex.get(edge.target);
+            const sourceIndex = urlToIndex.get(source);
+            const targetIndex = urlToIndex.get(target);
 
             if (sourceIndex !== undefined && targetIndex !== undefined) {
-                const weight = edge.weight || 1.0;
-                incoming[targetIndex].push({ sourceIndex, weight });
-                outgoing[sourceIndex].push({ targetIndex, weight });
+                const w = weight || 1.0;
+                incoming[targetIndex].push({ sourceIndex, weight: w });
+                outgoing[sourceIndex].push({ targetIndex, weight: w });
             }
-        }
+        });
 
         // Initialize Scores
         const authScores = new Float64Array(N).fill(1.0);

packages/core/src/graph/metrics.ts

@@ -23,24 +23,23 @@ export interface Metrics {
 
 export function calculateMetrics(graph: Graph, _maxDepth: number): Metrics {
   const nodes = graph.getNodes();
-  const edges = graph.getEdges();
 
   const totalPages = nodes.length;
-  const totalEdges = edges.length;
+  const totalEdges = graph.edges.size;
 
   // Identify broken nodes
   const brokenNodes = new Set(nodes.filter(n => n.status >= 400 || n.status === 0).map(n => n.url));
 
   // Pre-compute outgoing edges per node for faster lookup
   const outgoingEdges = new Map<string, string[]>();
-  for (const edge of edges) {
-    let targets = outgoingEdges.get(edge.source);
+  graph.forEachEdge((source, target) => {
+    let targets = outgoingEdges.get(source);
     if (!targets) {
       targets = [];
-      outgoingEdges.set(edge.source, targets);
+      outgoingEdges.set(source, targets);
     }
-    targets.push(edge.target);
-  }
+    targets.push(target);
+  });
 
   // Populate brokenLinks per node
   for (const node of nodes) {

packages/core/src/graph/pagerank.ts

@@ -33,7 +33,6 @@ export class PageRankService {
         const neutralScoreWhenFlat = options.neutralScoreWhenFlat ?? 50;
 
         const allNodes = graph.getNodes();
-        const allEdges = graph.getEdges();
 
         // 1. Filter Eligible Nodes
         const eligibleNodes = allNodes.filter(node => {
@@ -71,16 +70,16 @@ export class PageRankService {
         const outWeights = new Float64Array(nodeCount);
         const incoming: { sourceIndex: number, weight: number }[][] = new Array(nodeCount).fill(null).map(() => []);
 
-        for (const edge of allEdges) {
-            const sourceIndex = urlToIndex.get(edge.source);
-            const targetIndex = urlToIndex.get(edge.target);
+        graph.forEachEdge((source, target, weight) => {
+            const sourceIndex = urlToIndex.get(source);
+            const targetIndex = urlToIndex.get(target);
 
             if (sourceIndex !== undefined && targetIndex !== undefined) {
-                const weight = edge.weight || 1.0;
-                incoming[targetIndex].push({ sourceIndex, weight });
-                outWeights[sourceIndex] += weight;
+                const w = weight || 1.0;
+                incoming[targetIndex].push({ sourceIndex, weight: w });
+                outWeights[sourceIndex] += w;
             }
-        }
+        });
 
         // Identify sinks
         const sinks: number[] = [];