In a scenario where a function needs to access the this keyword of a containing object, should an arrow function be used?
- Yes, always
- No, never
- It depends
- Only in classes
Arrow functions should not be used in this scenario because they do not bind their own "this" and instead inherit it from the enclosing scope. This can lead to unintended behavior when trying to access the "this" keyword of a containing object.
In a scenario where a function receives a complex object as an argument, how can destructuring assignment enhance code readability and maintenance?
- It has no effect on code readability
- It makes code more complex
- It simplifies the extraction of values from the object
- It can only be used with primitive data types
When a function receives a complex object as an argument, using destructuring assignment can significantly enhance code readability and maintenance. By specifying the necessary properties directly in the function parameter, developers can easily understand which values the function expects. This not only simplifies the code but also reduces the need for repeated object property access, making the code more efficient and easier to maintain.
Consider a scenario where you are handling multiple independent API calls. How would the approach differ using Promises compared to callbacks?
- Promises allow for better parallel execution
- Callbacks are more suitable for independent calls
- Promises are slower for independent calls
- Callbacks lead to callback hell
When dealing with multiple independent API calls, Promises offer a significant advantage by allowing for better parallel execution. Unlike callbacks, which may result in nested structures (callback hell), Promises provide a more elegant solution through chaining, resulting in cleaner and more maintainable code.
Consider a function designed to format a date. How would you use default parameters to provide flexibility in the format?
- Utilize default parameters to allow users to specify the format, such as formatDate(date, format = "YYYY-MM-DD").
- Use default parameters for individual components like day, month, and year, enabling customization while maintaining a default format.
- Allow a default format but also accept an optional format parameter, giving users the ability to override the default if needed.
- Use default parameters to set a default format but allow users to pass a custom formatting function, giving maximum flexibility.
Default parameters in JavaScript allow you to assign default values to function parameters. In the context of formatting a date, default parameters can be used to provide a default format, and users can override this by passing their desired format as an argument. This provides a balance between having a predefined format and allowing customization based on user needs.
What is the outcome of trying to mutate the properties of an object declared with const?
- Mutation is allowed
- Mutation is not allowed
- Mutation is allowed, but with restrictions
- Mutation is allowed only for primitive properties
When an object is declared with const, its reference cannot be reassigned, but the properties can be mutated. It's important to note that const protects the reference, not the content. So, attempting to reassign the entire object will result in an error, but modifying its properties is permissible.
When implementing a recursive function in ES6, what considerations should be made regarding stack overflow?
- Tail call optimization eliminates the risk of stack overflow in all cases.
- It's essential to handle base cases properly to avoid stack overflow.
- Stack overflow is unavoidable in recursive functions in ES6.
- Increasing the stack size is the only solution to prevent overflow.
When implementing recursive functions in ES6, it's crucial to handle base cases effectively to prevent stack overflow. While tail call optimization can help in some cases, it's not universally guaranteed, making proper base case management a fundamental consideration.
__________ recursion refers to a situation where a recursive function calls itself multiple times within a single step.
- Nested
- Infinite
- Deep
- Tail
In-depth content in the explanation. Recursive functions that call themselves multiple times within a single step are known as deep recursion. This occurs when a function calls itself within a nested structure, leading to multiple recursive calls in one step.
What is functional composition in the context of JavaScript?
- Combining multiple functions to produce a new function
- Transforming data types in JavaScript
- Declaring variables within functions
- Utilizing loops in JavaScript
Functional composition involves combining multiple functions to produce a new function. This technique is commonly used to create more complex and reusable functions by chaining together simpler ones. It promotes a modular and clean coding style, enhancing code readability and maintainability. Understanding functional composition is crucial for writing efficient and scalable JavaScript code.
In a scenario where multiple API calls are made and you need to wait for all of them to complete, which Promise method would be most appropriate?
- Promise.all()
- Promise.race()
- Promise.any()
- Promise.resolve()
When dealing with multiple asynchronous operations that should all complete before proceeding, Promise.all() is the appropriate method. It takes an array of promises and resolves when all of them have resolved. This ensures that you wait for all API calls to complete before moving forward.
How do Promises facilitate handling multiple asynchronous AJAX requests concurrently?
- Promises use a single-threaded model, limiting concurrency.
- Promises cannot handle multiple asynchronous requests concurrently.
- Promises allow chaining, enabling sequential handling of requests.
- Promises support Promise.all() for concurrent handling of multiple requests.
Promises facilitate handling multiple asynchronous AJAX requests concurrently through the Promise.all() method. It takes an array of promises and returns a new promise that fulfills with an array of the resolved values when all promises in the iterable argument have been fulfilled.