The spread operator can effectively be used to create a shallow ______ of an object or an array.
- Copy
- Clone
- Reference
- Duplicate
The spread operator can effectively be used to create a shallow "Clone" of an object or an array. When you use the spread operator, it creates a new object or array with the same values as the original, but it is a separate entity in memory. This is known as a shallow clone.
You need to build a middleware that performs multiple operations asynchronously before passing control to the next middleware. How can you ensure that your middleware handles errors effectively and does not hang the application?
- Implement error handling within the middleware using try-catch blocks and call the next middleware with an error parameter if an error occurs. Use next(err) to propagate the error to Express's default error handler.
- Avoid error handling in middleware to improve performance, rely on Express's default error handling, and use a timeout to prevent the middleware from hanging indefinitely.
- Use callbacks instead of promises or async/await for asynchronous operations within the middleware to avoid potential errors, and rely on external tools to monitor and handle errors.
- Use the process.exit() method to terminate the application if an error occurs within the middleware to prevent it from hanging.
To ensure that a middleware handles errors effectively and does not hang the application, it's best practice to implement error handling within the middleware itself using try-catch blocks and call next(err) to propagate the error to Express's default error handler. Option 2 is not recommended as it bypasses proper error handling, and options 3 and 4 are unconventional and may cause issues.
What are the implications of choosing an improper data type for a field in a database schema on storage and performance?
- Increased storage space, slower queries
- Decreased storage space, faster queries
- Improved data integrity
- No impact on storage or performance
Choosing an improper data type can lead to increased storage space and slower queries. For example, using a large data type for a small piece of data wastes space and may result in more I/O operations, slowing down queries. It's crucial to choose appropriate data types to optimize storage and performance.
How can you import a specific item from a module in ES6+?
- import { item } from 'module';
- import 'module' item;
- import item from 'module';
- include { item } from 'module';
In ES6+ JavaScript, you can import a specific item from a module using the syntax import { item } from 'module';. This allows you to selectively import only the items you need from a module. The other options are not valid import syntax in ES6+.
Where should you ideally store your static files like images, CSS, and JavaScript in an Express.js project?
- In the project root directory
- In a dedicated static directory
- Inside the node_modules directory
- In a separate database
In an Express.js project, it's a best practice to store your static files like images, CSS, and JavaScript in a dedicated static directory. This helps organize your project and makes it clear which files are intended to be served statically. Storing them in the project root, node_modules, or a database is not a recommended practice for serving static files.
The 'highWaterMark' option in Node.js streams denotes the ______ of the internal buffer.
- size
- rate
- capacity
- length
In Node.js streams, the 'highWaterMark' option denotes the capacity of the internal buffer. This value determines how much data the stream can buffer before it starts to pause the data source.
You are managing a project with multiple dependencies, and you want to ensure that upgrading a dependency doesn't break the project due to API changes. How would you specify the version numbers of the dependencies in the package.json file?
- ^1.0.0
- ~1.0.0
- 1.0.0
- 1.x.x
To ensure that only patch-level changes are allowed for your dependencies, you should use the ~ (tilde) prefix. This will allow for bug fixes (patch versions) but prevent breaking changes (minor or major versions).
To handle uncaught exceptions in a Node.js application, you can use process.on('______', callback).
- unhandledRejection
- process.error
- exception
In Node.js, you can handle uncaught exceptions by using the process.on('unhandledRejection', callback) event. This allows you to capture unhandled promise rejections and take appropriate actions.
You are building a game where a player must answer a series of questions. How would you structure the control flow to handle the player’s responses and determine the next action or question based on the response?
- if...else if...else statements
- switch statement
- try...catch statements
- while loop
To handle the player's responses and determine the next action or question based on the response in a game, you would typically use a series of if...else if...else statements. These conditional statements allow you to evaluate multiple conditions and execute corresponding code blocks based on the player's response. The switch statement can also be used, but it's better suited for cases where you need to match a single value to multiple possible cases. try...catch is used for error handling, and a while loop is generally not suitable for handling player responses in this context.
What is the role of the extends property in an ESLint configuration file?
- It specifies the file extensions to be linted.
- It extends the code editor with ESLint features.
- It defines the list of plugins to use.
- It inherits configurations from other configurations.
The extends property in an ESLint configuration file allows you to inherit configurations from other configurations. It's a way to reuse or build upon existing ESLint configurations, making it easier to enforce consistent coding standards across projects.
When an error occurs in Node.js, the error object is typically an instance of __________.
- Error
- Exception
- ErrorObject
- Err
In Node.js, when an error occurs, the error object is typically an instance of the built-in Error object. This object contains valuable information about the error, such as a message and a stack trace.
Which data type in JavaScript can be used to store a sequence of characters?
- char
- sequence
- string
- text
In JavaScript, the string data type is used to store a sequence of characters. The char data type doesn't exist in JavaScript, and neither sequence nor text are valid data types for this purpose.