Nest.js

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Q.1 How do you implement custom validation logic for DTOs in Nest.js?

You can create custom validation pipes and decorators to enforce custom validation rules on DTOs.

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Q.2 What is the purpose of the @nestjs/websockets package?

The @nestjs/websockets package provides tools for building WebSocket-based real-time applications in Nest.js.

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Q.3 Explain the concept of global and module-scoped providers in Nest.js.

Global providers are available throughout the application, while module-scoped providers are limited to the module in which they are defined.

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Q.4 How can you implement authentication using OAuth2 in Nest.js?

Libraries like Passport.js provide OAuth2 strategies for implementing OAuth2 authentication in Nest.js.

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Q.5 How can you implement a task scheduler in Nest.js?

You can use libraries like node-schedule or the @nestjs/schedule module for task scheduling.

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Q.6 Explain the role of the Nest.js ExecutionContext.

The ExecutionContext provides information about the current request context, allowing you to access request and response objects.

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Q.7 How do you handle database transactions in Nest.js applications?

Database transactions can be managed using TypeORM or other database libraries that support transactions.

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Q.8 What is the purpose of the Nest.js nestjsx/crud package?

This package provides tools for building RESTful CRUD APIs in Nest.js applications.

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Q.9 How can you implement real-time data synchronization between clients using WebSockets in Nest.js?

You can use libraries like Socket.io to implement real-time data synchronization.

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Q.10 Explain the concept of Exception Filters in Nest.js.

Exception Filters are used to handle exceptions and transform them into meaningful error responses.

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Q.11 How do you implement database seeding in Nest.js applications?

You can create seed scripts or use database migration tools to populate the database with initial data.

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Q.12 What is the purpose of the Nest.js @nestjs/swagger package?

It allows you to generate Swagger documentation for your API endpoints, making it easier to document your APIs.

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Q.13 How can you handle authentication using third-party providers like Google or Facebook in Nest.js?

Passport.js provides strategies for handling authentication with third-party providers.

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Q.14 Explain the use of Guards for role-based authorization in Nest.js.

Guards can be used to check the roles or permissions of users before allowing access to certain routes.

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Q.15 What is the purpose of the Nest.js @nestjs/testing module?

The @nestjs/testing module provides utilities and tools for unit and integration testing of Nest.js applications.

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Q.16 How do you implement database migrations in Nest.js using TypeORM?

TypeORM provides a migration system that allows you to manage database schema changes.

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Q.17 What is the purpose of the @nestjs/graphql package in Nest.js?

The @nestjs/graphql package simplifies the creation of GraphQL APIs using Nest.js.

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Q.18 How can you implement request logging and tracing in Nest.js applications?

You can use middleware and request interceptors to log and trace requests.

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Q.19 Explain the concept of Dynamic Modules in Nest.js.

Dynamic Modules allow for the dynamic registration of providers and configuration based on runtime conditions.

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Q.20 How do you handle internationalization (i18n) in Nest.js applications?

Libraries like i18n can be used to implement internationalization in Nest.js applications.

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Q.21 What is the purpose of GraphQL subscriptions in Nest.js?

GraphQL subscriptions enable real-time data updates for clients.

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Q.22 How can you implement rate limiting in Nest.js applications to protect against abuse?

Rate limiting can be implemented using libraries like express-rate-limit to prevent abuse of your APIs.

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Q.23 Explain the concept of Nest.js interceptors and their use cases.

Interceptors allow you to intercept and modify requests and responses, making them useful for logging, caching, and other tasks.

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Q.24 How do you manage environment-specific configuration in Nest.js applications?

The @nestjs/config module can be used to load configuration variables from environment files based on the current environment (e.g., development, production).

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Q.25 What is the purpose of the Nest.js @nestjs/swagger package in Nest.js applications?

The @nestjs/swagger package generates Swagger documentation for your API endpoints, making it easier to document and share your APIs.

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Q.26 How can you handle input validation for GraphQL mutations in Nest.js?

You can use DTOs and validation pipes to validate input data for GraphQL mutations.

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Q.27 What is the role of the Nest.js Execution Context in request processing?

The Execution Context provides access to the current request and response objects, allowing you to inspect and manipulate the request context.

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Q.28 How can you implement WebSocket authentication in Nest.js applications?

WebSocket authentication can be implemented by validating tokens or session cookies when clients connect to WebSocket endpoints.

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Q.29 Explain the role of Dependency Injection in Nest.js.

Dependency Injection manages the creation and sharing of instances among components, promoting modularity and testability.

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Q.30 How do you handle cross-cutting concerns like logging in Nest.js applications?

Cross-cutting concerns can be handled using Nest.js middleware and interceptors to centralize functionality.

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Q.31 What is the purpose of using the @nestjs/common package in Nest.js applications?

The @nestjs/common package provides core decorators and utility classes used throughout Nest.js applications.

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Q.32 How do you handle database migrations with Prisma in Nest.js applications?

Prisma provides its own migration system for managing database schema changes in Nest.js applications.

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Q.33 Explain the concept of Validation Pipes in Nest.js.

Validation Pipes are used to automatically validate incoming data against defined DTOs, ensuring data integrity.

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Q.34 How do you implement health checks and monitoring endpoints in Nest.js applications?

Health checks and monitoring endpoints can be implemented as separate routes or middleware to monitor the application's health and status.

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Q.35 What is the purpose of the Nest.js Microservices module, and when would you use it?

The Microservices module allows you to build distributed systems with Nest.js using message-driven communication. It's useful for scaling and decoupling services.

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Q.36 How do you handle versioning of APIs in Nest.js?

API versioning can be achieved by defining version-specific routes or controllers.

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Q.37 What is the purpose of the Nest.js @nestjs/serve-static package?

The @nestjs/serve-static package enables serving static files, such as images or CSS, in Nest.js applications.

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Q.38 Explain the concept of Context in GraphQL and how it is used in Nest.js.

Context in GraphQL represents the shared data and state available to all resolvers in a request. In Nest.js, you can use it to pass information like authentication tokens to resolvers.

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Q.39 How can you implement custom decorators in Nest.js to simplify repetitive tasks?

You can create custom decorators to encapsulate common functionality or metadata and apply them to classes, methods, or properties.

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Q.40 What is the purpose of GraphQL Fragments, and how do you use them in Nest.js?

GraphQL Fragments allow you to define reusable selections of fields in queries. In Nest.js, you can use them to simplify complex GraphQL queries.

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Q.41 How do you implement serverless functions with Nest.js using platforms like AWS Lambda or Azure Functions?

You can package your Nest.js application as a serverless function and deploy it to serverless platforms.

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Q.42 What is the purpose of the Nest.js @nestjs/cqrs package?

The @nestjs/cqrs package provides tools for implementing the Command Query Responsibility Segregation (CQRS) pattern in Nest.js.

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Q.43 How can you optimize the performance of a Nest.js application?

Performance optimization can be achieved through techniques like caching, database indexing, load balancing, and minimizing blocking operations.

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Q.44 What is the purpose of the Nest.js @nestjs/microservices package?

The @nestjs/microservices package provides tools for building microservices architectures in Nest.js applications.

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Q.45 How can you implement database pooling in Nest.js applications to improve scalability?

Database pooling can be configured using libraries like TypeORM to efficiently manage database connections.

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Q.46 What is the purpose of the Nest.js @nestjs/sse package, and how can you use it for server-sent events?

The @nestjs/sse package enables server-sent events in Nest.js applications for real-time data streaming to clients.

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Q.47 How do you implement GraphQL subscriptions in Nest.js to provide real-time updates to clients?

GraphQL subscriptions can be implemented using the @nestjs/graphql package, allowing clients to subscribe to changes in data.

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Q.48 What is the purpose of the Nest.js @nestjs/bull package, and how can you use it for job queue processing?

The @nestjs/bull package integrates the Bull job queue library into Nest.js applications, allowing for efficient background job processing.

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Q.49 What is the purpose of GraphQL directives, and how do you use them in Nest.js?

GraphQL directives are used to add metadata and control the execution of queries. In Nest.js, you can define and use custom directives to modify query behavior.

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Q.50 How do you implement data validation for query parameters in Nest.js routes?

Data validation for query parameters can be implemented using Pipes to ensure incoming data conforms to expected types and constraints.

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Q.51 What are guards, and how can you use them to protect routes in Nest.js applications?

Guards are used to protect routes based on conditions. You can create custom guards to implement authentication and authorization logic.

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Q.52 Explain the purpose of the Nest.js @nestjs/swagger package in the context of generating API documentation.

The @nestjs/swagger package generates Swagger/OpenAPI documentation for your Nest.js APIs based on decorators and metadata, making it easier for developers to understand and consume your API.

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Q.53 How can you implement transactional behavior in Nest.js services that interact with databases?

You can use the @Transaction decorator provided by TypeORM or other database libraries to manage transactions in Nest.js services.

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Q.54 What is the purpose of the Nest.js Guards and Pipes combination, and how does it enhance the request processing flow?

Combining Guards and Pipes allows you to perform authorization and data validation in a structured and sequential manner in the request processing flow.

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Q.55 Explain how to set up authentication with OAuth2 using the @nestjs/passport package in Nest.js.

To set up OAuth2 authentication, you can configure Passport.js strategies for OAuth2 providers like Google or Facebook and use the @nestjs/passport package for integration.

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Q.56 How can you handle WebSocket disconnections and reconnections in a Nest.js WebSocket Gateway?

You can implement WebSocket disconnection and reconnection handling by listening to relevant events and maintaining state in your WebSocket Gateway.

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Q.57 What is the purpose of the Nest.js Prisma Service and how do you use it to interact with a Prisma-powered database?

The Nest.js Prisma Service is a custom service that encapsulates database interactions using Prisma. You can inject it into your components to perform database operations.

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Q.58 Explain the role of the Nest.js APP_GUARD constant and how you can use it to apply a global guard.

The APP_GUARD constant is used to apply a global guard that affects all routes. You can provide it in your application configuration to apply the guard globally.

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Q.59 How can you implement pagination for GraphQL queries in Nest.js, allowing clients to retrieve a specific subset of data?

You can use pagination arguments in GraphQL queries to specify the number of items to skip and the maximum number of items to retrieve, allowing clients to paginate through data.

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Q.60 What is the purpose of the Nest.js @nestjs/pino package, and how does it enhance logging in Nest.js applications?

The @nestjs/pino package integrates the Pino logger into Nest.js applications, providing faster and more efficient logging capabilities.

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Q.61 How can you perform database seeding in Nest.js applications to populate the database with initial data?

You can create seed scripts or use Prisma migrations with seed data to populate the database with initial records.

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Q.62 Explain the use of the Nest.js @nestjs/terminus package for health checks and graceful shutdown in Nest.js applications.

The @nestjs/terminus package provides health checks and graceful shutdown functionality, allowing you to monitor the application's health and handle shutdown procedures.

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Q.63 How do you configure a Nest.js application to support multiple environments, such as development, staging, and production?

You can use environment variables and configuration files with the @nestjs/config package to manage application configuration for different environments.

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Q.64 What is the purpose of the Nest.js @nestjs/swagger API tags and how do they help organize API documentation?

API tags in the @nestjs/swagger package allow you to categorize and organize endpoints in your generated Swagger documentation, improving clarity and navigation.

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Q.65 How can you implement authentication using a custom strategy with Passport.js in Nest.js applications?

You can create a custom Passport.js strategy and use it to implement authentication logic specific to your application's needs in Nest.js.

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Q.66 Explain how to implement rate limiting based on IP addresses in Nest.js APIs to prevent abuse.

You can implement rate limiting based on IP addresses using middleware like express-rate-limit to restrict the number of requests from a single IP address within a specified timeframe.

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Q.67 What is the purpose of the Nest.js CLI plugin system, and how can you extend the CLI with custom commands and generators?

The Nest.js CLI plugin system allows you to extend the CLI with custom commands and generators to streamline project setup and development tasks.

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Q.68 How can you configure cross-origin resource sharing (CORS) in a Nest.js application to allow or restrict access from different domains?

You can configure CORS settings using the @nestjs/common package or by adding custom middleware to control which origins can access your API.

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Q.69 Explain how to implement request validation for GraphQL mutations in Nest.js to ensure that input data adheres to defined rules.

You can use DTOs and validation pipes to validate input data for GraphQL mutations and enforce data integrity.

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Q.70 How can you optimize database queries in Nest.js applications to improve query performance and reduce resource usage?

Database query optimization techniques include using indexes, limiting data retrieval, and minimizing the number of queries by utilizing joins and caching.

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Q.71 What is the purpose of the Nest.js @nestjs/azure-func package, and how can you use it to create Azure Functions with Nest.js?

The @nestjs/azure-func package enables the creation of serverless Azure Functions using Nest.js, making it easier to build and deploy serverless applications.

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Q.72 Explain the concept of Nest.js Guards for handling route parameters, and how do they differ from standard route guards?

Route parameter guards are used to validate and transform route parameters before they reach the route handler, providing a more specialized form of route protection.

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Q.73 How can you handle authentication using JSON Web Tokens (JWT) in a Nest.js application, and what are the benefits of JWT-based authentication?

JWT-based authentication involves issuing and validating JWT tokens to authenticate users. It offers benefits like stateless authentication and reduced server load.

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Q.74 What is Nest.js?

Nest.js is a framework for building efficient, scalable, and maintainable server-side applications using TypeScript.

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Q.75 Explain the architecture of Nest.js.

Nest.js follows a modular architecture with modules, controllers, and services.

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Q.76 What is Dependency Injection in Nest.js?

Dependency Injection is a design pattern used in Nest.js for managing and injecting dependencies into components, such as controllers and services.

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Q.77 What are providers in Nest.js?

Providers are classes annotated with @Injectable and are used for defining services, repositories, and other dependencies.

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Q.78 What is Middleware in Nest.js?

Middleware functions in Nest.js are used to process requests before they reach the route handler.

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Q.79 Explain the role of Guards in Nest.js.

Guards are used to control access to routes and protect them from unauthorized access.

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Q.80 What is the purpose of Interceptors in Nest.js?

Interceptors allow you to intercept and modify the response and request objects.

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Q.81 How do you handle exceptions in Nest.js?

Exceptions can be handled globally using exception filters or at the route level using the @UseFilters decorator.

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Q.82 What are DTOs (Data Transfer Objects) in Nest.js?

DTOs are used to define the shape of data sent and received by APIs, helping to validate and document data structures.

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Q.83 Explain the concept of Pipes in Nest.js.

Pipes are used for data transformation and validation before it reaches the route handler.

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Q.84 What is Serialization in Nest.js?

Serialization is the process of converting response objects into JSON.

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Q.85 How can you configure CORS in Nest.js?

CORS (Cross-Origin Resource Sharing) can be configured in the main.ts file or using the @nestjs/common package.

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Q.86 What is the purpose of Swagger in Nest.js?

Swagger is used to automatically generate API documentation based on your Nest.js application's routes and DTOs.

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Q.87 Explain the concept of Guards in Nest.js.

Guards are used to protect routes based on certain conditions, such as authentication or authorization.

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Q.88 How do you handle authentication in Nest.js?

Authentication can be handled using Passport.js, JWT tokens, or other authentication libraries.

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Q.89 What is GraphQL and how does Nest.js support it?

GraphQL is a query language for APIs. Nest.js provides tools and libraries like Apollo Server to support GraphQL.

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Q.90 What is WebSockets and how can you implement them in Nest.js?

WebSockets allow for real-time communication. Nest.js supports WebSockets through libraries like Socket.io and WebSocket Gateway.

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Q.91 How do you handle file uploads in Nest.js?

File uploads can be handled using libraries like Multer.

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Q.92 What is the purpose of the @nestjs/testing module?

It provides utilities for testing Nest.js applications and their components.

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Q.93 What is the difference between a synchronous and asynchronous provider in Nest.js?

Synchronous providers are instantiated immediately, while asynchronous providers may have asynchronous setup logic.

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Q.94 How do you handle database connections in Nest.js?

You can use libraries like TypeORM or Sequelize to manage database connections.

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Q.95 Explain the role of the @nestjs/schedule module.

It provides a scheduling system for running tasks at specified intervals.

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Q.96 How can you handle versioning of your APIs in Nest.js?

API versioning can be handled using routing and versioned controllers.

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Q.97 What is the purpose of the @nestjs/config module?

It helps with configuration management, allowing you to load environment variables and configuration files.

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Q.98 Explain Nest.js microservices.

Nest.js can be used to build microservices architecture using libraries like NATS or gRPC.

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Q.99 How do you enable logging in Nest.js?

Logging can be enabled using the built-in Logger service or third-party logging libraries.

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Q.100 What is the purpose of Guards in Nest.js?

Guards are used to protect routes and perform pre-route processing.

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Q.101 How do you handle database migrations in Nest.js using TypeORM?

TypeORM provides a migration system for managing database schema changes.

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Q.102 Explain the purpose of DTOs (Data Transfer Objects) in Nest.js.

DTOs define the structure of data exchanged between the client and server.

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Q.103 What is the role of decorators in Nest.js?

Decorators are used to define metadata and configure various aspects of Nest.js components.

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Q.104 How do you implement pagination in Nest.js APIs?

Pagination can be implemented using query parameters like page and limit.

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Q.105 Explain the use of @nestjs/graphql for GraphQL APIs.

@nestjs/graphql simplifies the creation of GraphQL APIs using Nest.js.

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Q.106 How do you handle authentication with JWT in Nest.js?

JWT (JSON Web Tokens) can be implemented for authentication and authorization in Nest.js.

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Q.107 What is the purpose of Dependency Injection in Nest.js?

Dependency Injection manages the creation and sharing of instances among components.

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Q.108 How do you handle environment variables in Nest.js?

Environment variables can be loaded and accessed using libraries like dotenv or the @nestjs/config module.

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Q.109 Explain the purpose of GraphQL subscriptions in Nest.js.

GraphQL subscriptions allow real-time data updates for clients.

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Q.110 How can you implement internationalization (i18n) in Nest.js?

Libraries like i18n can be used to implement internationalization in Nest.js applications.

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Q.111 What is the purpose of DTO validation in Nest.js?

DTO validation ensures that incoming data conforms to expected shapes and constraints.

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Q.112 How do you implement rate limiting in Nest.js?

Rate limiting can be implemented using libraries like express-rate-limit.

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Q.113 What are Dynamic Modules in Nest.js?

Dynamic Modules allow for the dynamic registration of providers.

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Q.114 Explain the use of the @nestjs/swagger module.

@nestjs/swagger provides decorators for generating Swagger documentation.

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Q.115 How can you handle session-based authentication in Nest.js?

Session-based authentication can be implemented using libraries like Passport.js with session support.

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Q.116 What is the purpose of the Nest.js Testing module?

The Testing module provides utilities for unit testing Nest.js applications.

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Q.117 How can you implement a cron job in Nest.js?

Cron jobs can be implemented using libraries like node-cron.

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Q.118 What is the purpose of the @nestjs/platform-express package?

It provides Express integration for Nest.js applications.

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Q.119 How do you handle data validation and sanitization in Nest.js?

Data validation and sanitization can be handled using Pipes and DTOs.

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Q.120 What is the purpose of the @nestjs/graphql package?

It provides tools for building GraphQL APIs with Nest.js.

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Q.121 How do you handle WebSocket connections in Nest.js?

WebSocket connections can be managed using libraries like Socket.io or WebSocket Gateway.

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Q.122 What is the purpose of the Nest CLI (Command Line Interface)?

The Nest CLI is a command-line tool that helps with project generation, scaffolding, and development tasks.

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Q.123 How do you implement authentication using Passport.js in Nest.js?

You can use the @nestjs/passport package along with Passport.js strategies to implement authentication.

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Q.124 How can you implement pagination and sorting in Nest.js APIs?

Pagination and sorting can be implemented by processing query parameters like page, limit, and sort.

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Q.125 Explain the concept of Prisma in Nest.js.

Prisma is an ORM (Object-Relational Mapping) tool used for database access and query building in Nest.js applications.

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Q.126 What are the benefits of using TypeScript in Nest.js?

TypeScript provides static typing, better code organization, and enhanced tooling for Nest.js applications.

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Q.127 How do you handle file uploads with GraphQL in Nest.js?

Libraries like graphql-upload can be used to handle file uploads in GraphQL mutations.

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Q.128 Explain the role of the @nestjs/platform-express package.

This package provides integration with the Express.js framework for Nest.js applications.

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Q.129 How do you configure the Nest.js application to use a different HTTP server, such as Fastify?

You can pass a Fastify instance to the NestFactory function during application bootstrap.

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Q.130 What is the purpose of the @nestjs/swagger package in Nest.js?

It provides decorators and utilities for generating Swagger documentation for your API endpoints.

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Q.131 How can you implement caching in Nest.js applications?

Caching can be implemented using libraries like cache-manager for in-memory caching or Redis for distributed caching.

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Q.132 Explain the purpose of the @nestjs/typeorm package.

The @nestjs/typeorm package provides integration with the TypeORM ORM library for database access in Nest.js applications.

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Q.133 How do you handle session management in Nest.js applications?

Session management can be implemented using libraries like express-session for Express.js-based applications.

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Q.134 What is the purpose of the @nestjs/jwt package in Nest.js?

The @nestjs/jwt package provides tools for working with JSON Web Tokens (JWT) in Nest.js applications.

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