In Node.js, the Event Loop operates on a single ________, which makes it suitable for I/O-bound tasks.
- Thread
- Core
- Process
- Module
In Node.js, the Event Loop operates on a single Core, not a thread or process. This single-threaded event loop design is one of the key features of Node.js, making it suitable for I/O-bound tasks as it can efficiently handle asynchronous operations without the overhead of multiple threads or processes.
The concept of defining a blueprint for the data in the database is known as ________.
- Schema
- Query
- Index
- Aggregate
The concept of defining a blueprint for the data in the database is known as "Schema." A schema defines the structure, relationships, constraints, and integrity rules of the data stored in a database.
When an EventEmitter instance experiences an error, the typical event that is emitted is ______.
- 'error'
- 'exception'
- 'fail'
- 'warning'
In Node.js, when an EventEmitter instance experiences an error, the typical event that is emitted is 'error'. This event allows you to handle errors that occur within event listeners attached to the EventEmitter.
How does the closure concept relate to higher-order functions in JavaScript?
- Closures are only used in lower-order functions.
- Higher-order functions cannot create closures.
- Higher-order functions often return closures, allowing them to encapsulate and manage private data.
- Closures are unrelated to higher-order functions.
Closures and higher-order functions are closely related in JavaScript. Higher-order functions often return closures, which can encapsulate and manage private data, creating a powerful mechanism for maintaining state and data privacy.
If an error is not handled by custom error-handling middleware in Express, it is handled by the ______.
- next()
- defaultErrorHandler
- express.handleError()
- console.error()
If an error is not handled by custom error-handling middleware in Express, it is handled by the default Express error handler, which is often referred to as the "defaultErrorHandler." This handler sends an error response to the client and logs the error details.
n CRUD operations, which operation is used to modify existing data?
- Create
- Read
- Update
- Delete
The Update operation in CRUD (Create, Read, Update, Delete) operations is used to modify existing data in the system. It allows you to make changes to existing records.
The Access-Control-Allow-Methods header in CORS specifies which HTTP ________ are allowed.
- methods
- verbs
- headers
- origins
The Access-Control-Allow-Methods header in CORS specifies which HTTP methods are allowed for cross-origin requests. It should include a comma-separated list of HTTP methods such as GET, POST, PUT, DELETE, etc.
Improper handling of dependencies and devDependencies can lead to larger ________ sizes when deploying an application.
- bundle
- package
- container
- memory
Improper handling of dependencies and devDependencies can lead to larger bundle sizes when deploying an application. When you include unnecessary dependencies, your application's bundle size increases, impacting load times and performance.
In Express.js, to serve static files, you generally use the ______ middleware.
- static
- middleware
- server
- file
In Express.js, to serve static files, you generally use the static middleware. This middleware allows you to serve files such as images, CSS, and JavaScript to clients.
You are developing a large-scale application and notice that some modules are loading slowly. How would you optimize the loading of modules to improve the application's performance?
- Minify and bundle all modules into a single file.
- Use lazy loading to load modules on-demand.
- Increase server hardware resources.
- Reduce the number of modules.
To optimize the loading of modules in a large-scale application, you should use lazy loading (Option b). Lazy loading allows modules to be loaded only when they are needed, reducing initial load times and improving performance. Minification (Option a) is also a valid optimization technique but may not address the issue of slow initial loading. Increasing server resources (Option c) and reducing the number of modules (Option d) are not effective solutions for optimizing module loading.