Is it possible to dynamically import modules using ES6 syntax, and how does it differ for named and default exports?
- Yes, the syntax is the same for both
- Yes, but the syntax differs
- No, dynamic imports are not supported in ES6
- Only named exports can be dynamically imported
It is possible to dynamically import modules using ES6 syntax. The syntax is the same for both named and default exports, providing a dynamic way to load modules when needed. The key difference lies in how the imported values are accessed in the code.
Dynamic imports return a __________ which resolves to the module.
- Promise
- Object
- Function
- String
Dynamic imports in JavaScript return a Promise, which resolves to the module. This asynchronous approach allows for the dynamic loading of modules, enhancing the efficiency of the application by loading resources only when needed. The Promise returned by the dynamic import can be further utilized to handle the module after it has been successfully loaded. Understanding this concept is crucial for efficient code splitting and optimizing performance in JavaScript applications.
Can you define currying in JavaScript?
- A technique of transforming a function with multiple arguments into a sequence of functions
- A method to manipulate arrays in JavaScript
- A way to create objects using constructors
- An approach to handling asynchronous code
Currying is a technique in JavaScript that involves transforming a function with multiple arguments into a sequence of functions, each taking a single argument. This allows for partial application of the function, making it more flexible and reusable. Currying is particularly useful in functional programming and can lead to more concise and modular code. A solid understanding of currying is beneficial for developers working with JavaScript.
How can the spread operator facilitate the process of adding elements to state arrays in a React component without mutating the original state?
- Create a new array using the spread operator, add elements, and set the state
- Use the Array.push() method to add elements to the state array
- Directly modify the existing state array
- Utilize the Array.concat() method to add elements to the state array
The spread operator is used in React to avoid mutating the state directly. Creating a new array with the spread operator, adding elements, and then setting the state ensures immutability and proper state management in React components.
What happens when you add duplicate elements to a Set?
- Ignored, Overwritten, Error, Concatenated
- Overwritten, Ignored, Concatenated, Error
- Concatenated, Overwritten, Ignored, Error
- Ignored, Concatenated, Error, Overwritten
When you add duplicate elements to a Set in JavaScript, they are ignored. Unlike Arrays or Objects, Sets only allow unique values, ensuring that the Set contains only distinct elements. Adding a duplicate element does not result in an error, and the Set remains unchanged.
How does error handling differ in async/await compared to traditional promise-based approaches?
- Both handle errors in the same way
- Async/await uses try...catch for error handling
- Promises use try...catch for error handling
- Async/await relies on callback functions
In async/await, errors are handled using the familiar try...catch block, making it easier to write and read asynchronous code. This improves the debugging experience compared to chaining .then() and .catch() in promise chains.
If you are creating a function to navigate through a tree-like data structure, how would recursion aid in this process?
- Recursively call the function for each child node, allowing traversal through the entire tree.
- Utilize a for loop to iterate over each level of the tree structure.
- Apply the Array.prototype.map method to map through the tree nodes.
- Use the Array.prototype.filter method to filter out unwanted nodes in the tree.
Recursion is instrumental in navigating a tree-like data structure by allowing the function to traverse through each level of the tree effortlessly. The recursive call on each child node ensures a thorough exploration of the entire structure. Other options lack the inherent nature of recursion for tree traversal.
What happens if a class in ES6 does not have a constructor?
- It throws an error
- It automatically creates an empty constructor
- It inherits the constructor from the parent class
- It is not possible to have a class without a constructor
In ES6, if a class does not have a constructor, a default constructor is automatically created. This default constructor is empty and does nothing. This behavior helps in cases where a class does not require any specific initialization logic in its constructor.
To override a static method in a subclass, you need to use the same method name and the _________ keyword.
- super
- override
- static
- extend
To override a static method in a subclass, you use the same method name as the parent class and the super keyword. This allows you to call the parent class's static method while providing a new implementation in the subclass.
What is the significance of side effects in a function in terms of functional programming?
- Enhances performance
- Allows for state changes outside the function
- Simplifies code structure
- Ensures security
Side effects, such as changing external state, are discouraged in functional programming as they make it harder to reason about the behavior of a function and can lead to unexpected issues.
In the map method, what happens if the callback function doesn't return any value?
- It throws an error
- It returns undefined for each element
- It skips the current element in the resulting array
- It returns an array of null values
If the callback function in the map method doesn't return any value (implicitly or explicitly), each corresponding element in the resulting array will have the value undefined. It's essential to ensure that the callback function produces meaningful output to avoid unexpected results.
To prevent infinite recursion, it is important to define a __________ that stops the recursion.
- Base case
- Recursive case
- Break statement
- Counter variable
In recursive functions, a base case is crucial to terminate the recursion. It is the condition that, when met, stops the function from calling itself endlessly.