NodeJS Fundamentals: async/await

The text discusses migrating a Node.js order processing service to async/await to address performance bottlenecks caused by callback-heavy code. Async/await improves code readability and error handling by making asynchronous code appear synchronous, crucial in Node.js's single-threaded environment. It details use cases like API handlers, queue processing, scheduled tasks, and database transactions, providing a REST API example using Express.js and PostgreSQL. The system architecture involves microservices orchestrated with Kubernetes, communicating via gRPC/REST, using message queues for asynchronous tasks, and load balancers for traffic distribution. Benchmarking showed improved response times and requests per second after the migration, attributed to reduced event loop blocking. Security practices like input validation, error handling, rate limiting, and authentication are emphasized. The CI/CD pipeline includes linting, testing, building, dockerizing, and deploying stages, while monitoring uses pino, prom-client, and OpenTelemetry for logging, metrics, and tracing. Testing involves unit, integration, and end-to-end tests with mocking for external API calls and simulating failures. Common pitfalls like forgetting await, using await in loops, and ignoring promise rejections are highlighted, along with best practices such as using Promise.all, centralizing error handling, and writing comprehensive tests.