You are designing a real-time data processing system where data needs to be transformed before being sent to another service. How would you implement streams in Node.js to ensure smooth data transformation and transmission?
- Use a single function to transform data and send it directly to the service.
- Implement a Readable stream to receive data, transform it with a Transform stream, and then pipe it to a Writable stream that sends it to the service.
- Store all incoming data in memory, transform it, and then send it to the service.
- Use asynchronous callbacks to process data and send it to the service as it arrives.
In a real-time data processing system, you should implement streams. Use a Readable stream to receive data, transform it with a Transform stream, and then pipe it to a Writable stream that sends it to the service. This approach allows for smooth data transformation and transmission without storing large amounts of data in memory.
What is the difference between process.nextTick() and setImmediate() in Node.js?
- process.nextTick() executes callbacks before any I/O events. setImmediate() executes callbacks after I/O events.
- process.nextTick() is used for synchronous execution, while setImmediate() is used for asynchronous execution.
- process.nextTick() is a browser API, and setImmediate() is a Node.js API.
- process.nextTick() has a higher priority than setImmediate().
The primary difference between process.nextTick() and setImmediate() in Node.js is their timing. process.nextTick() executes callbacks before any I/O events, allowing you to schedule code to run immediately after the current operation, while setImmediate() executes callbacks after the current I/O event loop phase, providing a smoother event loop. The other options do not accurately describe the difference.
When destructuring arrays, using the rest operator will result in a new array containing the ______ elements.
- First
- Last
- Middle
- Remaining
When destructuring arrays using the rest operator, it will result in a new array containing the "Remaining" elements. The rest operator collects the remaining elements of an array into a new array.
Your application allows users to upload and share documents. You need to implement a solution to scan uploaded documents for malicious content. What considerations and strategies would you employ to ensure the security of the uploaded files?
- Utilize antivirus software to scan files on the server.
- Implement a content filtering system with regular expression checks.
- Use machine learning-based content analysis to detect malicious content.
- Skip content scanning to improve performance.
Employing machine learning-based content analysis is an effective way to detect malicious content in uploaded files. It can adapt and improve over time, providing better security. The other options are less robust and may not adequately protect against malicious uploads.
Which part of the semantic versioning number (e.g. 1.2.3) is incremented for backwards-compatible bug fixes?
- Major version
- Minor version
- Patch version
- Build version
In SemVer, the 'patch' version is incremented for backwards-compatible bug fixes. This is done to indicate that changes made in this version are intended to address bugs without introducing breaking changes or new features.
The ______ event of the request object in the http module is emitted when the request body is being received.
- data
- request
- body
The data event of the request object in the http module is emitted when the request body is being received. This event allows you to handle incoming data in chunks, which is particularly useful for processing large request bodies without consuming excessive memory.
You are developing an Express.js application that needs to validate user input on a specific route. How would you implement middleware to efficiently validate input for that route?
- Use the app.use method to add a middleware function to the specific route that performs input validation.
- Include the validation logic directly within the route handler function for the specific route.
- Define a separate middleware function and use app.use to apply it globally for all routes.
- Implement input validation as a part of the route's URL parameters.
To efficiently validate user input for a specific route in Express.js, you should create a dedicated middleware function using app.use and apply it only to the specific route in question. This approach keeps the route handler clean and separates concerns. The other options are less efficient or incorrect approaches.
You are tasked with developing a real-time notification system in Node.js. Which feature of the Events module would be most beneficial in implementing this?
- event.emitOnce()
- event.removeAllListeners()
- event.once()
- event.removeListener()
In a real-time notification system, you would want to ensure that each notification is only sent once to the respective listeners. The event.once() method allows you to do this as it automatically removes the listener after it's been invoked once, ensuring efficient and clean handling of notifications. The other options are useful for managing listeners but do not guarantee a one-time notification.
Which Express.js function is used to create an instance of a router object?
- app.route()
- express.router()
- express.Router()
- app.useRouter()
In Express.js, you create an instance of a router object using express.Router(). Routers are used to modularize routes and middleware. The other options do not create router instances in the standard Express.js way.
How can you handle error events emitted by the request object in the http module?
- request.on('error', (error) => { /* Handle error here */ });
- request.error((error) => { /* Handle error here */ });
- request.catch((error) => { /* Handle error here */ });
- request.onError((error) => { /* Handle error here */ });
To handle error events emitted by the request object in the http module, you can use the request.on('error', (error) => { /* Handle error here */ }); syntax. This allows you to register a callback function to handle errors when they occur during the HTTP request.
What is the primary advantage of using connection pooling when interacting with a database?
- Improved Performance
- Enhanced Security
- Simplified Query Language
- Reduced Data Redundancy
Connection pooling improves performance. It allows reusing established database connections, reducing the overhead of creating and closing connections for every database operation. This results in faster response times and efficient resource usage.
The async keyword is used before a function to make it return a ________.
- Promise
- Callback
- Generator
- Function
The async keyword is used before a function to make it return a Promise. It allows you to work with asynchronous code in a more synchronous-like fashion by enabling the use of await within the function.