Node.js Developer: Free Skill Evaluation

Variables Data Types Operators Conditions Loops Functions Arrays Objects Arrow functions Destructuring Spread Rest Optional chaining Nullish coalescing Template literals Modules First-class functions Callbacks Higher-order functions Closures Lexical scope Prototype Prototype chain Classes Inheritance Composition Custom error classes Operational vs programmer errors Error propagation Promise Resolve Reject Then Catch Finally Sequential calls Concurrent calls Failures Timeouts Promise.all Promise.allSettled Promise.race Promise.any Task queue Microtasks Promises Timers Primitives Tuples Function typing Return typing Interfaces Aliases Unions Intersections Generics Utility types Narrowing Discriminated unions Mapped types concepts Conditional-type awareness 100 Questions 75 Coding Tasks Node.js runtime V8 Libuv concepts Npm Package.json CommonJS ECMAScript Modules Pending callbacks Poll Check Close callbacks Process.nextTick() Event Loop Blocking Readable Writable Duplex Transform Large files Streams Uploads Exports Buffer Filesystem APIs Paths Event Listener Emitter Worker Threads Spawn Exec Fork Clustering & Process Scaling Http Server Application Router Middleware Error middleware Request Response Express Architecture Resources URLs HTTP semantics Statelessness Body Params Query Headers Api Error Design Api Pagination Filtering & Sorting Api Versioning Idempotency Endpoints Schemas Status codes Auth requirements TypeScript Express Validation Standardized errors Pagination Search OpenAPI SELECT INSERT UPDATE DELETE WHERE GROUP BY Joins Subqueries CTE Window functions Transactions Indexes Tables Relationships Constraints JSONB concepts Locks ACID Isolation Concurrent writes Rollback Read Committed Repeatable Read Serializable concepts Execution plans Query shape Connection pooling Schema Models Relations Queries Migrations Typeorm Awareness Database Collections Documents BSON ObjectId CRUD Embed Reference Hooks Relationships concepts Match Project Group Lookup Unwind Sort Facet Single field Compound Unique TTL Sql Vs Nosql Sessions Tokens JWT OAuth2 Password hashing Salts Password reset Brute-force protection Access Refresh Claims Expiry Signature Rotation Revocation concepts Rbac Object-Level Authorization Authorization Code PKCE Client Credentials Scopes Identity providers SQL injection NoSQL injection Broken access control Mass assignment concepts CORS CSRF XSS awareness Rate limits Secret exposure Dependency vulnerabilities Organization Users Authentication RBAC Tenant isolation Audit trail Controllers Providers Dependency Injection Nestjs Modules Transformation Authorization Response transforms Metrics Logging Cross-cutting behavior Exception Filters Custom Decorators Nestjs Configuration PostgreSQL Prisma/TypeORM MongoDB Identity Customer Catalog Orders Payments Caching Counters Temporary state Rate limiting Sessions concepts Cache-Aside Cache Invalidation Cache Stampede Distributed Locks Email Reports Imports Notifications Payments reconciliation Queue Worker Retries Concurrency Scheduled jobs Job State Idempotent Jobs Signatures Duplicate delivery Messaging Collaborative applications Connections Rooms Events Reconnect Scaling concepts Messages Online status Redis concepts for scaling Progress Feeds AI tokens Multipart Limits Content type Storage Aws S3 Presigned Urls Fixed Window Sliding Window Token Bucket concepts Service boundaries Loose coupling Independent deployment Database ownership Modular Monolith REST Queues GRPC awareness Nestjs Microservices Broker Topic Partition Producer Consumer Consumer Group Offset Keys At-most-once At-least-once Exactly-once concepts Retry Dead-letter topics Poison messages Idempotent Consumers Exchange Routing Acknowledgements Aws Sqs/Sns Distributed Transactions Choreography Orchestration Compensation Transactional Outbox Timeout Exponential backoff Jitter Circuit breaker concepts NestJS Redis Kafka Saga Outbox Unit Integration Contract End-to-End Services Domain rules Utilities Mocking HTTP Auth DB Database Tests Testcontainers Awareness Contract Testing Load Stress Spike Soak Requests/sec Event-loop delay CPU Memory P50 P95 P99 Event Loop Lag Heap Allocation Leaks Caches References Global collections Event listeners Unbounded caches Cpu Profiling Connection pool Slow queries Hit Ratio Misses Evictions Correlation Ids Request rate Error rate Latency Event-loop lag Queue depth DB pool usage Trace Span Context propagation Distributed Tracing Liveness Readiness Dependency health CPU 100% API latency high DB healthy CPU 35% Requests waiting DB pool 100% Slow SQL Long transactions Connection leaks Consumer throughput Errors Downstream DB Partitions Webhooks Listeners Cache Retained objects Image Container Dockerfile Multi-stage builds Networks Volumes Environment variables Docker Compose Files Permissions Processes Environment Ports Logs Pods Deployments ConfigMaps Secrets Probes Resource limits Autoscaling concepts Rolling deployments Aws Iam Aws Ec2 Rds S3 Lambda Api Gateway Sqs Sns Partition key Sort key Access patterns Secondary indexes concepts Alarms Ci/Cd Github Actions Jenkins Awareness Rolling Blue/Green Canary Clean Architecture Entity Value Object Aggregate Bounded Context Domain Event Repository Factory Strategy Adapter Observer Facade Low-Level Design URL Shortener Payment Backend Chat Backend Notification Platform Order Management System Ticket Booking File Processing Platform Learning Platform Multi-Tenant SaaS Event Processing System Mutation Resolver N+1 concerns Protobuf concepts RPC Service contracts Internal service communication Api Gateway Pattern Serverless Architecture LLM API calls Streaming Structured output Tool-call concepts Embeddings RAG awareness Usage tracking Prompt injection awareness Unauthorized retrieval API keys Quotas Output validation Cost limits