Fix Voyage AI rerank response parsing

packages/components/nodes/retrievers/VoyageAIRetriever/VoyageAIRerank.test.ts

@@ -0,0 +1,94 @@
+import axios from 'axios'
+import { Document } from '@langchain/core/documents'
+import { VoyageAIRerank } from './VoyageAIRerank'
+
+jest.mock('axios')
+
+describe('VoyageAIRerank', () => {
+    beforeEach(() => {
+        jest.clearAllMocks()
+    })
+
+    it('maps Voyage API data responses back to the reranked documents', async () => {
+        const reranker = new VoyageAIRerank('test-key', 'rerank-2', 2)
+        const documents = [
+            new Document({ pageContent: 'alpha', metadata: { source: 'a' } }),
+            new Document({ pageContent: 'bravo', metadata: { source: 'b' } }),
+            new Document({ pageContent: 'charlie', metadata: { source: 'c' } })
+        ]
+
+        ;(axios.post as jest.Mock).mockResolvedValue({
+            data: {
+                data: [
+                    { index: 2, relevance_score: 0.97 },
+                    { index: 0, relevance_score: 0.86 }
+                ]
+            }
+        })
+
+        const result = await reranker.compressDocuments(documents, 'letters')
+
+        expect(axios.post).toHaveBeenCalledWith(
+            'https://api.voyageai.com/v1/rerank',
+            {
+                model: 'rerank-2',
+                query: 'letters',
+                documents: ['alpha', 'bravo', 'charlie'],
+                top_k: 2
+            },
+            expect.objectContaining({
+                headers: expect.objectContaining({
+                    Authorization: 'Bearer test-key'
+                })
+            })
+        )
+        expect(result.map((doc) => doc.pageContent)).toEqual(['charlie', 'alpha'])
+        expect(result.map((doc) => doc.metadata.relevance_score)).toEqual([0.97, 0.86])
+    })
+
+    it('continues to support legacy Voyage API results responses', async () => {
+        const reranker = new VoyageAIRerank('test-key', 'rerank-lite-1', 1)
+        const documents = [new Document({ pageContent: 'alpha', metadata: {} }), new Document({ pageContent: 'bravo', metadata: {} })]
+
+        ;(axios.post as jest.Mock).mockResolvedValue({
+            data: {
+                results: [{ index: 1, relevance_score: 0.91 }]
+            }
+        })
+
+        const result = await reranker.compressDocuments(documents, 'letters')
+
+        expect(result.map((doc) => doc.pageContent)).toEqual(['bravo'])
+        expect(result[0].metadata.relevance_score).toBe(0.91)
+    })
+
+    it('falls back to original documents when Voyage API returns an invalid result shape', async () => {
+        const reranker = new VoyageAIRerank('test-key', 'rerank-lite-1', 2)
+        const documents = [new Document({ pageContent: 'alpha', metadata: {} }), new Document({ pageContent: 'bravo', metadata: {} })]
+
+        ;(axios.post as jest.Mock).mockResolvedValue({
+            data: {}
+        })
+
+        await expect(reranker.compressDocuments(documents, 'letters')).resolves.toBe(documents)
+    })
+
+    it('skips rerank results that point outside the provided documents', async () => {
+        const reranker = new VoyageAIRerank('test-key', 'rerank-lite-1', 2)
+        const documents = [new Document({ pageContent: 'alpha', metadata: {} }), new Document({ pageContent: 'bravo', metadata: {} })]
+
+        ;(axios.post as jest.Mock).mockResolvedValue({
+            data: {
+                data: [
+                    { index: 3, relevance_score: 0.99 },
+                    { index: 1, relevance_score: 0.88 }
+                ]
+            }
+        })
+
+        const result = await reranker.compressDocuments(documents, 'letters')
+
+        expect(result.map((doc) => doc.pageContent)).toEqual(['bravo'])
+        expect(result[0].metadata.relevance_score).toBe(0.88)
+    })
+})

packages/components/nodes/retrievers/VoyageAIRetriever/VoyageAIRerank.ts

@@ -34,17 +34,25 @@ export class VoyageAIRerank extends BaseDocumentCompressor {
         const data = {
             model: this.model,
             query: query,
-            documents: documents.map((doc) => doc.pageContent)
+            documents: documents.map((doc) => doc.pageContent),
+            top_k: this.k
         }
         try {
-            let returnedDocs = await axios.post(this.VOYAGEAI_RERANK_API_URL, data, config)
+            const returnedDocs = await axios.post(this.VOYAGEAI_RERANK_API_URL, data, config)
+            const rerankResults = returnedDocs.data?.data ?? returnedDocs.data?.results
+            if (!Array.isArray(rerankResults)) {
+                throw new Error('Invalid response format from Voyage API: rerank results must be an array')
+            }
+
             const finalResults: Document<Record<string, any>>[] = []
-            returnedDocs.data.results.forEach((result: any) => {
+            rerankResults.forEach((result: any) => {
                 const doc = documents[result.index]
-                doc.metadata.relevance_score = result.relevance_score
-                finalResults.push(doc)
+                if (doc) {
+                    doc.metadata.relevance_score = result.relevance_score
+                    finalResults.push(doc)
+                }
             })
-            return finalResults.splice(0, this.k)
+            return finalResults.slice(0, this.k)
         } catch (error) {
             return documents
         }