> nestjs-search

Elasticsearch integration and Sync patterns. Use when integrating Elasticsearch or implementing search index sync in NestJS. (triggers: **/*.service.ts, **/search/**, Elasticsearch, CQRS, Synchronization)

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SKILL.mdnestjs-search

Search Engine & Full-Text

Priority: P1 (OPERATIONAL)

Full-text search implementation with Elasticsearch and database patterns.

  • Pattern: CQRS (Command Query Responsibility Segregation).
    • Write: To Primary Database (Postgres/MySQL). Source of Truth.
    • Read (Complex): To Search Engine (Elasticsearch, OpenSearch, MeiliSearch). Optimized for filtering, fuzzy search, and aggregation.

Synchronization (The Hard Part)

  • Dual Write (Anti-Pattern): await db.save(); await es.index();.
    • Why: Partial failures leave data inconsistent. Slows down HTTP response.
  • Event-Driven (Recommended):
    1. Service writes to DB.
    2. Service emits EntityUpdated.
    3. Event Handler (Async) pushes to Queue (BullMQ).
    4. Worker indexes document to Search Engine with retries.
  • CDC (Golden Standard): Change Data Capture (Debezium). Connects directly to DB transaction log. No app conceptual overhead, but higher ops complexity.

Organization

  • Module: Encapsulate the client in a SearchModule.
  • Abstraction: Create generic SearchService<T> helpers.
    • indexDocument(id, body)
    • search(query, filters)
  • Mapping: Use class-transformer to map Entities to "Search Documents". Search docs should be flatter than Relational entities constraints.

Testing

  • E2E: Do not mock the search engine in critical E2E flows.
  • Docker: Spin up elasticsearch:8 container in the test harness to verify indexing works.

🚫 Anti-Patterns

  • Do NOT use standard patterns if specific project rules exist.
  • Do NOT ignore error handling or edge cases.

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github stars341
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first seenMar 17, 2026
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┌ repo

HoangNguyen0403/agent-skills-standard
by HoangNguyen0403
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┌ tags

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