Default parameters in a function are used when no argument or ________ is passed.
- undefined
- nan
- nan
- value
Default parameters in a function are used when no argument or undefined is passed. In JavaScript, if a parameter is not passed or is explicitly passed as undefined, the default value assigned to that parameter is used.
What is the key difference in loading dependencies in ES6 Modules compared to CommonJS?
- Imports are hoisted in ES6 Modules
- Synchronous loading in ES6 Modules
- Asynchronous loading in ES6 Modules
- No loading differences
In ES6 Modules, dependencies are loaded asynchronously, allowing for better performance and parallelism. This is in contrast to CommonJS, which loads modules synchronously.
In ES6, __________ methods are not enumerable in a class definition.
- static
- prototype
- constructor
- get
In ES6, static methods are not enumerable in a class definition. Static methods are attached to the class itself rather than its instances, and they are not iterated over when enumerating the properties of a class. This distinction is important when dealing with class-related operations.
To handle multiple AJAX requests concurrently and wait for all to complete, use Promise._______.
- all
- race
- any
- chain
To handle multiple AJAX requests concurrently and wait for all to complete, use Promise.all(). This method takes an array of promises and waits until all of them are resolved or any one is rejected.
If you're building a function to fetch user data and then fetch related posts based on that data, how would you structure your Promise chain?
- Nested Promises
- Promise.all()
- Promise.chain()
- Async/Await
You would structure your Promise chain using nested promises. This involves chaining .then() handlers to ensure the sequence of asynchronous operations. This allows you to fetch user data first and then, based on that data, fetch related posts in a structured manner.
To ensure the uniqueness of a Symbol, it is created using Symbol(__________), where the argument is optional.
- key'
- id'
- description'
- optional'
In JavaScript, Symbols are used to create unique identifiers. The argument passed to Symbol() is optional and can be used to provide a description for debugging purposes. Example: const mySymbol = Symbol('This is a description');
ES6 mixins can be seen as an alternative to traditional ___________ in object-oriented programming.
- Inheritance
- Encapsulation
- Polymorphism
- Abstraction
The correct option is Inheritance. ES6 mixins provide an alternative to traditional inheritance in object-oriented programming. With mixins, you can compose functionality from multiple sources without the need for a deep inheritance hierarchy, promoting a more modular and flexible code structure.
Describe the implementation of an async function that awaits user input and then processes it.
- Utilize prompt for user input within the async function
- Implement a callback for user input and await its resolution
- Use await with a promise-based input function
- Incorporate async/await with setTimeout for user input
To implement an async function awaiting user input, you can use await in combination with a promise-based input function. This ensures that the function pauses execution until user input is received, maintaining the asynchronous nature of the application.
In a function that generates HTML content, how would template literals enhance code readability and maintainability?
- They allow embedding variables directly in the string, reducing concatenation complexity.
- They provide a more concise syntax for creating HTML templates.
- They enable the use of complex expressions within the template, improving flexibility.
- They simplify the inclusion of special characters in the HTML content.
Template literals allow for more readable and maintainable code by directly embedding variables and expressions, reducing the need for complex string concatenation.
What is the difference in error handling between then/catch and async/await syntax?
- then/catch is used with synchronous code, and async/await is used with asynchronous code
- then/catch is promise-based, and async/await is generator-based
- then/catch is chaining, and async/await uses try/catch
- then/catch is for handling resolved values, and async/await is for handling rejections
The key difference lies in syntax and structure. then/catch involves chaining promises, while async/await uses a more synchronous and linear try/catch structure. async/await provides a cleaner and more readable way to handle asynchronous operations.