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.
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+.
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.
Which of the following is the primary role of middleware in Express.js?
- Handling client-side routing
- Handling server-side routing
- Managing HTTP requests and responses
- Creating database schemas
The primary role of middleware in Express.js is to manage HTTP requests and responses. Middleware functions are executed in the order they are defined in the Express application and can perform various tasks such as authentication, logging, and modifying request/response objects. They play a crucial role in the request/response cycle.
Which keyword is used to export multiple things from a module in JavaScript?
- import
- export
- require
- module
In JavaScript, the export keyword is used to export multiple things from a module. It allows you to specify which functions, objects, or variables should be accessible from outside the module. The import keyword is used for importing from modules, not exporting. The require and module keywords are used in CommonJS, a different module system.
How does JavaScript handle circular dependencies between modules?
- JavaScript throws an error and does not allow circular dependencies.
- JavaScript allows circular dependencies, and they are resolved at runtime.
- JavaScript handles circular dependencies by allowing them but ensuring that each module loads only once.
- Circular dependencies are not supported in JavaScript.
JavaScript allows circular dependencies, but it ensures that each module is only executed once. This is achieved through a mechanism called "module caching."
When handling errors in an async function, if an error is not caught within the function, it will cause the returned Promise to be in a ________ state.
- Pending
- Fulfilled
- Rejected
- Completed
When an uncaught error occurs in an async function, the returned Promise will be in a "Rejected" state. In the Promise lifecycle, it can start as "Pending," move to "Fulfilled" upon success, or "Rejected" upon an error.
Why would you use the global object to store data in a Node.js application?
- To share data between different Node.js modules.
- To encapsulate data and prevent it from being accessed globally.
- To improve application performance by reducing memory usage.
- To ensure data persistence across application runs.
The global object in Node.js can be used to store data that needs to be shared between different Node.js modules. It acts as a global namespace for variables and allows you to share data across different parts of your application. The other options do not accurately describe the common use case for the global object.
How does semantic versioning handle pre-release versions and build metadata?
- Pre-release versions are denoted with a hyphen and can include additional labels and numbers. Build metadata is indicated with a plus sign.
- Pre-release versions use square brackets to specify additional labels, and build metadata uses parentheses.
- Pre-release versions are marked with a plus sign, and build metadata is indicated with a hyphen.
- Pre-release versions are not supported in semantic versioning.
Semantic versioning allows pre-release versions to be denoted with a hyphen, followed by additional labels and numbers, and build metadata is indicated with a plus sign. This is essential for managing versions during development and testing phases.
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.