How does inheritance of static methods differ from that of instance methods in ES6?
- Static methods cannot be inherited.
- Static methods are inherited through the prototype chain.
- Static methods are inherited using the extends keyword.
- Static methods are inherited through the super keyword.
In ES6, static methods are inherited through the prototype chain, just like instance methods. The key difference lies in how they are called and accessed. The extends keyword is used to inherit static methods, making them accessible through the derived class. Option B is the correct answer.
What is the primary purpose of the async keyword in a function declaration?
- Enables the function to return a Promise
- Specifies that the function can be called asynchronously
- Defines a function that can only be executed in an asynchronous manner
- Marks a function as an asynchronous event handler
The async keyword is used to make a function return a Promise. This allows the use of await within the function, indicating that it contains asynchronous code.
Given a scenario where you need to process each character of a string individually, how would you utilize an iterator?
- Iterate through the string using a for loop
- Use the Array.from() method to convert the string to an array and then iterate
- Utilize the string's forEach method
- Use the for...of loop to iterate over the string
In this scenario, using the for...of loop is the most concise and readable way to iterate over each character of a string. The for...of loop works specifically for iterable objects, and strings are iterable in JavaScript. It simplifies the code and enhances readability.
What is a key difference between functional composition and method chaining?
- Method chaining involves calling methods directly on an object, while functional composition combines functions to create new functions
- Functional composition is only applicable in functional programming languages
- Method chaining can only be used with asynchronous functions
- All functions used in functional composition must be pure functions
Functional composition involves combining functions to create more complex ones, whereas method chaining is about calling methods directly on an object. Understanding this difference is crucial for designing clean and readable code.
What keyword is used to define a generator function in JavaScript?
- function*
- gen
- generator
- yield
The correct keyword to define a generator function in JavaScript is function*. It uses the asterisk (*) after the function keyword. This syntax indicates that the function is a generator. Options b) and c) are incorrect, and d) is used within the generator function to yield values.
Can dynamic imports be used in place of traditional static imports?
- Yes, always
- No, never
- It depends on the use case
- Only in Node.js environments
Dynamic imports cannot always replace traditional static imports. They are suitable for scenarios where modules are needed dynamically at runtime, but static imports are still necessary for modules required during the application's initialization.
How does dynamic import (import()) differ from static import (import ... from) in ES6?
- Deferred loading at runtime
- Resolved during compilation
- Allows importing entire modules as a single object
- Used for importing only specific exports
Dynamic import allows loading a module at runtime, which can be beneficial for code splitting and lazy loading. Static import, on the other hand, is resolved during compilation.
In a project management tool, you need to ensure each task is unique but also maintain their insertion order. Which data structure would you use?
- Set
- Array
- WeakSet
- Map
In this case, an Array is the most appropriate choice. It allows you to maintain the order of tasks while ensuring uniqueness. Unlike Set, which only stores unique values without any specific order, an Array meets both requirements for this project management tool.
If you are required to iterate over a collection of objects representing users and perform an action on each, how would a for...of loop benefit over other loops?
- for loop
- for...in loop
- forEach loop
- for...of loop
The correct option is the for...of loop. It is specifically designed for iterating over iterable objects and works well with arrays and other collections. It directly provides the values, avoiding the need for indexing and making the code more readable. This is especially beneficial when iterating over objects representing users, as it simplifies the syntax and enhances code clarity.
Consider a scenario where you have to implement a function to compute factorial numbers. How would ES6 features enhance the implementation of this recursive function?
- Utilize the let and const declarations for improved variable scoping and clarity.
- Apply the var declaration for simplicity and compatibility.
- Use the arrow function syntax for concise and expressive code.
- Implement the function using the function keyword for better readability.
ES6 features like let and const provide block-level scoping, enhancing the clarity of variables in the recursive factorial function. The arrow function syntax also contributes to code conciseness, making the implementation more elegant. The other options either introduce potential issues or miss the advantages of ES6 features.