A ______ cache stores data in a shared location that can be accessed by multiple application instances.
- Shared
- Distributed
- Local
- In-Memory
A Distributed cache stores data in a shared location that can be accessed by multiple application instances. This allows multiple nodes of an application to share cached data, improving performance and reducing redundancy.
While working on a project, you are required to extract specific properties from objects and assign them to variables. How would you utilize destructuring assignment to efficiently accomplish this task, and what would you do to handle non-existent properties?
- const { prop1, prop2 } = sourceObject;
- const [prop1, prop2] = sourceObject;
- const { prop1, prop2 } = [sourceObject];
- const [prop1, prop2] = { ...sourceObject };
To efficiently extract specific properties from objects using destructuring assignment in JavaScript, you would use the syntax const { prop1, prop2 } = sourceObject;. This assigns the values of prop1 and prop2 from sourceObject to the corresponding variables. To handle non-existent properties, you can provide default values like const { prop1 = defaultValue1, prop2 = defaultValue2 } = sourceObject;. The other options are not correct ways to achieve this task.
In a sharded database architecture, how are Update operations handled across multiple shards?
- Updates are broadcast to all shards
- A central coordinator handles all updates
- Each shard independently handles updates for its data
- Updates are queued and processed sequentially
In a sharded database architecture, a central coordinator (Option 2) often handles updates that affect multiple shards. Each shard (Option 3) independently handles updates for its own data, but coordinated updates across shards typically require a central component. Options 1 and 4 are not common methods for handling updates in sharded databases.
The ______ command can be used to update the package.json file to match the actual versions installed in the node_modules directory.
- npm install
- npm update
- npm sync
- npm check
The npm update command can be used to update the package.json file to match the actual versions installed in the node_modules directory. This command will update the version numbers of packages in package.json based on the versions currently installed.
To optimize CRUD operations in a high-write-load scenario, employing ______ strategies like write-behind caching can be effective.
- Caching
- Synchronization
- Scaling
- Indexing
To optimize CRUD operations, caching strategies like write-behind caching can be effective, where data is cached and written back to the database asynchronously. Caching reduces the need to access the database for every write operation, improving performance.
You are designing a system with a high read/write ratio, requiring efficient database interactions. How would you configure Sequelize or Mongoose to minimize database load and optimize performance?
- Implement caching mechanisms.
- Use Sequelize's "findOneAndUpdate" method.
- Disable indexing on database columns.
- Increase the database connection pool size.
To optimize performance with a high read/write ratio, implementing caching mechanisms is a common strategy. Options 2, 3, and 4 are not recommended for this purpose. "findOneAndUpdate" is not related to optimizing read/write efficiency. Disabling indexing can harm performance, and increasing the connection pool size alone won't optimize database interactions.
In order to secure user passwords, it is best practice to store them using a ________ algorithm.
- Hashing
- Encryption
- Decryption
- Salting
To secure user passwords, it's best practice to store them using a hashing algorithm. Hashing takes the password and transforms it into a fixed-size string of characters (hash) using a one-way function. This makes it difficult to reverse-engineer the password from the stored hash.
What is the primary use of the Events module in Node.js?
- Managing file operations
- Handling asynchronous code
- Handling events and event-driven programming
- Defining custom data types
The primary use of the Events module in Node.js is to facilitate event-driven programming. It allows you to create, emit, and handle custom events, making it a fundamental part of building real-time and responsive applications. Options A, B, and D are not the primary purposes of the Events module.
In what scenario would you need to create a custom error class in Express.js?
- When you want to replace the built-in error classes
- When you want to provide additional metadata with the error
- When you need to handle synchronous errors
- When you want to suppress errors and continue execution
Creating a custom error class in Express.js is useful when you want to provide additional metadata with the error, such as error codes, status codes, or custom properties. This allows you to convey more context about the error to the client or developer. The other options are not typical use cases for custom error classes.
Which of the following scenarios is most suitable for incrementing the 'minor' version in semantic versioning?
- Adding new features or functionality in a backward-compatible manner.
- Fixing a critical security vulnerability that requires code changes.
- Refactoring the internal code structure without affecting external interfaces.
- Removing a public API that is no longer needed.
In semantic versioning, the 'minor' version should be incremented when new features or functionality are added in a backward-compatible manner. This indicates to users that they can safely update to the new version without worrying about breaking changes.