fix(node): rerank vector search results

nodejs/__test__/rerankers.test.ts

@@ -79,6 +79,18 @@ describe("rerankers", function () {
     expect(result).toHaveLength(2);
   });
 
+  it("returns relevance scores when reranking a vector search", async function () {
+    const result = await table
+      .vectorSearch([0.1, 0.1])
+      .limit(2)
+      .rerank(await RRFReranker.create())
+      .toArray();
+
+    expect(result).toHaveLength(2);
+    expect(result[0]._relevance_score).toBeCloseTo(1 / 60);
+    expect(result[1]._relevance_score).toBeCloseTo(1 / 61);
+  });
+
   it("does not keep process alive after rerank query", async function () {
     const script = `
 import * as lancedb from "./dist/index.js";

nodejs/lancedb/rerankers/index.ts

@@ -5,9 +5,9 @@ import { RecordBatch } from "apache-arrow";
 
 export * from "./rrf";
 
-// Interface for a reranker. A reranker is used to rerank the results from a
-// vector and FTS search. This is useful for combining the results from both
-// search methods.
+// Interface for a reranker. A reranker is used to rerank vector and hybrid
+// search results. For vector-only searches, query is empty and ftsResults is an
+// empty batch with the same schema as vecResults.
 export interface Reranker {
   rerankHybrid(
     query: string,