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.

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How can specific error handlers be created to respond to different error types in Express.js?

Use the try...catch block
Define multiple catch blocks
Use the app.error() middleware
Utilize the next(err) function with custom error classes

In Express.js, specific error handlers for different error types can be created by utilizing the next(err) function with custom error classes. This allows you to define error-handling middleware that can respond to specific error types based on their custom classes. The other options are not typically used for handling specific error types in Express.js.

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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.

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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.

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When using dynamic imports, the import() function returns a ________.

Promise
Callback
Function
Object

When using dynamic imports in JavaScript, the import() function returns a Promise. This Promise resolves to the module's namespace object once the module is loaded and ready for use.

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What is the primary purpose of the package-lock.json file in a Node.js project?

To store documentation for the project
To store a backup of the package.json file
To specify the version of Node.js to use
To lock the version of each package's dependencies

The primary purpose of the package-lock.json file in a Node.js project is to lock the version of each package's dependencies. This ensures that every developer working on the project uses the same versions of dependencies, preventing version conflicts and ensuring consistency across environments. The other options (To store documentation for the project, To store a backup of the package.json file, and To specify the version of Node.js to use) do not accurately describe the purpose of the package-lock.json file.

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What is the primary purpose of performance optimization in a Node.js application?

To reduce memory usage
To improve code readability
To increase the number of dependencies
To enhance application speed

The primary purpose of performance optimization in a Node.js application is to enhance application speed. While other factors like memory usage and code readability are important, the primary goal is to make the application run faster and respond more efficiently to user requests.

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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.

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What is the role of the error-handling middleware when dealing with unhandled promise rejections in Express?

It converts promise rejections into synchronous errors
It terminates the Node.js process to prevent unhandled rejections
It logs the unhandled promise rejection and continues execution
It captures unhandled promise rejections and sends them to the default error handler

The error-handling middleware in Express captures unhandled promise rejections and sends them to the default error handler. This allows you to handle unhandled promise rejections gracefully in your Express application. The other options are not the typical roles of error-handling middleware in this context.

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You are developing a user management system and need to design routes for CRUD operations. How would you structure the routes to follow RESTful principles in Express.js?

Use any route structure that suits your needs
Design routes like /createUser, /getUser, /updateUser, /deleteUser
Structure routes as /users, using HTTP methods (GET, POST, PUT, DELETE) to indicate CRUD operations
Create routes like /addUser, /fetchUser, /modifyUser, /removeUser

To follow RESTful principles in Express.js, you should structure routes as a resource, such as /users, and use HTTP methods (GET, POST, PUT, DELETE) to indicate CRUD operations on that resource. This approach aligns with RESTful conventions, making your API more intuitive and standardized. Option 2 doesn't follow RESTful principles, and Options 1 and 4 lack the structured approach recommended for RESTful APIs.

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