41.1 Hybrid search (keyword + vector)

The Problem

Vector search finds semantically similar content but misses exact matches. Keyword search finds exact terms but misses synonyms. Hybrid combines both.

Implementation

// hybrid-search.ts
async function hybridSearch(query: string, limit = 10) {
  // Parallel search with both methods
  const [vectorResults, keywordResults] = await Promise.all([
    vectorSearch(query, limit * 2),
    keywordSearch(query, limit * 2)
  ]);
  
  // Reciprocal Rank Fusion
  const scores = new Map();
  const k = 60; // Tuning parameter
  
  vectorResults.forEach((doc, rank) => {
    const score = 1 / (k + rank);
    scores.set(doc.id, (scores.get(doc.id) || 0) + score);
  });
  
  keywordResults.forEach((doc, rank) => {
    const score = 1 / (k + rank);
    scores.set(doc.id, (scores.get(doc.id) || 0) + score);
  });
  
  // Sort by combined score
  return [...scores.entries()]
    .sort((a, b) => b[1] - a[1])
    .slice(0, limit)
    .map(([id]) => getDocument(id));
}

Where to go next

• 41.2 Metadata filtering and access control