Why is it important to define the correct path for serving static files in Express.js?
- To improve security by hiding static files.
- To enhance performance by reducing load times.
- To avoid conflicts with route handling.
- To simplify the code structure.
Defining the correct path for serving static files in Express.js is important to avoid conflicts with route handling. If the path is not specified correctly, Express.js might mistakenly interpret a URL as a route, leading to unexpected behavior. The other options, while important, are not the primary reason for specifying the correct static file path.
You are designing a microservices architecture where different services need to access shared data. How would you implement caching to ensure data consistency across services?
- Distributed Caching
- Local Caching
- Centralized Database
- Data Replication
In a microservices architecture with shared data, Distributed Caching would be the ideal choice. Distributed caches ensure data consistency across services by replicating data across multiple cache nodes, making it accessible to all services while maintaining data integrity. Local Caching is limited to individual services, and Centralized Databases may introduce bottlenecks and fail to ensure data consistency. Data Replication can be complex and is not a direct caching strategy.
You are developing a Node.js library intended to be used as a dependency in other projects. How would you utilize the package.json and package-lock.json files to ensure that the consumers of your library do not face any versioning or dependency conflicts?
- Do not provide a package-lock.json file with your library
- Specify the exact versions of dependencies in your package.json
- Use wildcard (*) versions for dependencies in your package.json
- Ask consumers to manually update your library's dependencies
To ensure consumers do not face versioning or dependency conflicts, you should specify the exact versions of dependencies in your package.json. This guarantees that consumers get the same dependencies you tested with. Option 1 is not recommended, and options 3 and 4 can lead to conflicts and issues.
In Node.js, '______' is used to signify the end of a writable stream.
- finish
- close
- end
- complete
In Node.js, the 'end' event is used to signify the end of a writable stream. This event is emitted when all data has been written to the stream and it's safe to end it. The other options (finish, close, complete) are not typically used for this purpose.
Why is caching used in web applications?
- To reduce server load and improve performance
- To increase server load and slow down performance
- To secure user data
- To display error messages
Caching in web applications is used to reduce server load and improve performance by storing frequently accessed data, such as web pages or database query results, so that it can be quickly retrieved without the need to regenerate it. Caching helps in minimizing the need for redundant processing and data retrieval.
In Express.js, middleware functions have access to the request object, the response object, and the ______ function.
- next()
- send()
- app()
- router()
In Express.js, middleware functions have access to the request object (req), the response object (res), and a callback function commonly named next(). The next() function is used to pass control to the next middleware function in the chain.
Which of the following is the primary goal of input sanitization?
- Enhancing user experience.
- Ensuring data accuracy.
- Preventing cross-site scripting (XSS) attacks.
- Optimizing database performance.
The primary goal of input sanitization is to prevent cross-site scripting (XSS) attacks. It involves removing or encoding potentially dangerous characters from user input to ensure that it cannot be executed as script on a web page, thus enhancing web security.
Which of the following is an example of an Object Document Mapper (ODM) for MongoDB in Node.js?
- Mongoose
- Sequelize
- Knex
- TypeORM
Mongoose is a popular Object Document Mapper (ODM) for MongoDB in Node.js. It provides a structured way to interact with MongoDB, allowing developers to define schemas and models for their data. The other options, Sequelize, Knex, and TypeORM, are primarily used with relational databases and are not ODMs for MongoDB.
When dealing with CORS, the Access-Control-Allow-Credentials header should be set to true to allow ________ to be included in the request.
- cookies
- headers
- authentication
- origins
When dealing with CORS, the Access-Control-Allow-Credentials header should be set to true to allow cookies to be included in cross-origin requests. This is necessary when you want to make authenticated requests across origins.
You are developing a system with stringent data integrity requirements. How would you design the schema to enforce data integrity constraints and handle violations effectively?
- Use database triggers to enforce constraints.
- Implement application-level validation only.
- Apply foreign key constraints to maintain data relationships.
- Rely solely on user input validation.
Option (1) is a valid approach using database triggers to enforce constraints. Option (2) shouldn't be the sole method, as application-level validation can be bypassed. Option (3) is essential, especially for maintaining data relationships. Option (4) is not sufficient for ensuring data integrity on its own.