You are developing a function that needs to merge two objects, with the second object overwriting the properties of the first one if there is a conflict. How would you achieve this?
- Object.assign()
- Object.merge()
- Object.combine()
- Object.extend()
To merge two objects with property conflicts, you can use the Object.assign() method. It takes one or more source objects and copies their properties to a target object. If properties with the same name exist in the target object, they will be overwritten by the source object's properties.
What is the significance of defining relationships between different entities in a database schema?
- Improving data integrity and consistency
- Reducing data retrieval time
- Simplifying query complexity
- Increasing storage efficiency
Defining relationships in a database schema is crucial for improving data integrity and consistency. Relationships help maintain referential integrity, ensuring that data remains accurate and reliable when related records are updated or deleted. While relationships can impact query complexity and storage, their primary purpose is to maintain data quality.
How can closures be used to create private variables in JavaScript?
- By declaring variables with the private keyword inside a function.
- By defining variables in the global scope.
- By using the const keyword to declare variables.
- By declaring variables inside a function that is not accessible from outside the function.
Closures can be used to create private variables in JavaScript by declaring variables inside a function. These variables are not accessible from outside the function, effectively creating encapsulation and data hiding.
You are optimizing an application with significant read and write operations. What considerations would you need to address while implementing caching to balance read and write efficiency?
- Cache Invalidation
- Write-Through Caching
- Expiry-Based Caching
- Write-Behind Caching
When optimizing an application with significant read and write operations, Write-Through Caching is a crucial consideration. Write-Through Caching ensures that data is both read and written to the cache and the underlying data store simultaneously, maintaining consistency. Cache Invalidation and Expiry-Based Caching are more focused on read operations, and Write-Behind Caching can lead to data inconsistency if not managed carefully.
How can you set HTTP headers in the response object when using the http module?
- response.headers = {...}
- response.setHeader(name, value)
- response.setHeaders({...})
- response.addHeader(name, value)
To set HTTP headers in the response object when using the http module, you should use response.setHeader(name, value). This method allows you to set individual headers with their corresponding values. The other options are not valid methods for setting headers.
Which section in the package.json file specifies the entry point of a Node.js application?
- main
- start
- entry
- node
The main section in the package.json file specifies the entry point of a Node.js application. This is the JavaScript file that will be executed when you run your application using node. It is typically set to the main application file, e.g., index.js.
What is the proper way to handle errors in EJS views?
- try-catch
- error-handler middleware
- if-else
- throw
In EJS views, the proper way to handle errors is by using error-handler middleware in your Node.js application. This middleware can catch and handle errors, allowing you to display appropriate error pages or messages in your views. The other options (try-catch, if-else, and throw) are not typically used for handling errors in EJS views.
CORS is a security feature implemented by ________.
- Web browsers
- Server-side frameworks
- Client-side libraries
- Database systems
CORS (Cross-Origin Resource Sharing) is a security feature implemented by web browsers. It allows or restricts web applications running at one origin (domain) to make requests for resources located on a different origin.
How can cache stampede be mitigated in high-traffic applications?
- By using a cache eviction policy
- By implementing cache sharding
- By adding more cache nodes
- By using cache warming techniques
Cache stampede in high-traffic applications can be mitigated by using cache warming techniques. Cache warming involves preloading the cache with frequently accessed data, reducing the likelihood of cache misses and stampedes during high traffic.
You are experiencing slow query performance on a large dataset with millions of records. How would you identify and optimize the slow-performing queries?
- Use an Object-Relational Mapping (ORM) library
- Implement pagination for query results
- Create proper database indexes
- Increase server RAM
To optimize slow-performing queries on a large dataset, creating proper database indexes is crucial. Indexes can significantly speed up query performance by allowing the database to quickly locate relevant data. Options A and B might help with other aspects but do not directly address query performance. Increasing server RAM may not always resolve query performance issues related to large datasets.