[JS] RAG reranking throws TypeError following sample code from docs

[morganric]

Describe the bug
A clear and concise description of what the bug is. include full error messages.

I am trying to implement RAG reranking within my firebase functions application using Genkit, following this article:
https://firebase.google.com/docs/genkit/rag

I consistently hit this error:

Reranking failed with correct format: TypeError: Cannot read properties of undefined (reading 'map')

 at rerank (/Users/richardmorgan/Documents/dev/neuro/mvp/functions/node_modules/@genkit-ai/ai/lib/reranker.js:123:29)

To Reproduce
Steps to reproduce the behavior. Code samples.

here is an example of my code:

try {
console.log("Starting reranking process...");

    // Check if docs is valid
    if (!docs || !Array.isArray(docs) || docs.length === 0) {
      console.error("docs is invalid:", docs);
      throw new Error("Invalid docs array for reranking");
    }

    // Log the structure of the first document to debug
    console.log("First doc structure:", JSON.stringify(docs[0], null, 2));

    // Create a simpler query
    const queryText = aiPrompt.trim().substring(0, 500);
    // Limit length to be safe
    console.log("Using query text:", queryText);

    // Try reranking with direct document passing
    const rerankedDocs = await ai.rerank({
      reranker: semanticRanker512,
      query: queryText, // Try with plain text instead of Document object
      documents: docs, // Pass the retrieved docs directly
    });

    console.log("Reranking successful!");
    console.log("Number of reranked docs:", rerankedDocs.length);

    // Check the structure of the reranked docs
    if (rerankedDocs.length > 0) {
      console.log("First reranked doc structure:",
        JSON.stringify(rerankedDocs[0], null, 2));
    }

    // Include the reranked docs in the final response
    res.status(200).json({
      data: {
        success: true,
        message: "Mood assessment submitted successfully",
        timestamp: data.timestamp,
        aiRecommendations: aiResponse,
        aiDocs: docs,
        rerankedDocs: rerankedDocs,
      },
      status: "success",
    });
  } catch (error) {
    console.error("Detailed reranking error:", error);

    // Try another approach with explicit document conversion
    try {
      console.log("Attempting alternative reranking approach...");

      // Convert docs to a simpler format that the reranker might accept
      const simpleDocs = docs.map((doc) => {
        return {
          id: doc.metadata?.id ||
          `doc_${Math.random().toString(36).substring(7)}`,
          content: [{
            text: typeof doc.content === "string" ?
              doc.content :
              JSON.stringify(doc.content),
          }],
        };
      });

      console.log("Created simplified docs:", simpleDocs.length);

      // Try reranking with the simplified docs
      const altRerankedDocs = await ai.rerank({
        reranker: semanticRanker512,
        query: aiPrompt,
        documents: simpleDocs,
      });

      console.log("Alternative reranking successful!");

      // Include these alternative results
      res.status(200).json({
        data: {
          success: true,
          message: "Mood assessment submitted successfully",
          timestamp: data.timestamp,
          aiRecommendations: aiResponse,
          aiDocs: docs,
          rerankedDocs: altRerankedDocs,
        },
        status: "success",
      });
    } catch (secondError) {
      console.error("Both reranking approaches failed:", secondError);

      // Return response without the reranked docs
      res.status(200).json({
        data: {
          success: true,
          message: "Mood assessment submitted success (reranking failed)",
          timestamp: data.timestamp,
          aiRecommendations: aiResponse,
          aiDocs: docs,
        },
        status: "success",
      });
    }
  }

Expected behavior
A clear and concise description of what you expected to happen.

I expect a response containing a ranked array of docs with scores.

Screenshots
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Runtime (please complete the following information):

• OS: [e.g. Linux, MacOS]
• Version [e.g. 22]

MacOS 12.5

** Node version

• run node --version at paste here
  v22.2.0

Additional context
Add any other context about the problem here.