How can functional composition benefit the readability and maintainability of JavaScript code?
- Enhances code modularity
- Reduces side effects
- Encourages reuse of functions
- All of the above
Functional composition involves combining small, pure functions to create more complex ones, enhancing modularity, reducing side effects, and promoting code reuse. This leads to improved code readability and maintainability.
When using Promises with AJAX, handling network errors is done through the ______ method of the Fetch API.
- error
- fail
- catch
- reject
When using Promises with AJAX, handling network errors is done through the catch method of the Fetch API. The catch block allows you to handle any errors that occurred during the AJAX request.
What is the impact of using a pure function on the predictability and testability of code?
- Increases unpredictability
- Decreases testability
- Enhances predictability
- No impact on testability
Using pure functions in code enhances predictability by ensuring that the function's output is solely determined by its input, without relying on external state. This predictability simplifies testing, as pure functions can be easily isolated and tested independently, contributing to overall code reliability.
The ability to _________ values during destructuring allows for more flexible data manipulation.
- skip
- swap
- default
- mutate
The ability to set default values during destructuring provides flexibility in handling undefined or missing values, enhancing data manipulation capabilities.
Side effects in a function include things like modifying a _________ or logging to the console.
- Variable
- Object
- Array
- State
Side effects can include modifying external state, like changing the value of a variable or an object, which goes against the principles of pure functions.
Using the rest operator in function parameters collects the rest of the arguments into an ________.
- Object
- Array
- Iterable
- String
The rest operator (...) in function parameters is used to collect the rest of the arguments into an array. It allows a function to accept a variable number of arguments.
For a function that calculates a discount on a price, how can default parameters be used to make the function adaptable to different discount strategies?
- Use default parameters to set a default discount strategy, like calculateDiscount(price, discount = 0.1).
- Allow users to pass a discount strategy as a parameter and use default parameters to handle cases where no strategy is provided.
- Utilize default parameters for individual discount components, such as percentage and fixed amount, offering flexibility in discount calculation.
- Set default parameters for both price and discount strategy, allowing users to calculate discounts with a default strategy or a custom one.
Default parameters can enhance the adaptability of a discount calculation function. By setting a default discount strategy, users have the option to either accept the default or provide a custom strategy. This design allows for a default behavior while accommodating different discount strategies based on user preferences or specific use cases.
What is the primary purpose of the Symbol type in ES6?
- Representing unique values
- Enhancing string manipulation
- Simplifying arithmetic operations
- Controlling loop iterations
The primary purpose of the Symbol type in ES6 is to represent unique values. Symbols are guaranteed to be unique, and they are often used to create object properties that won't collide with properties of the same name. This uniqueness makes Symbols useful in scenarios where identifier collision is a concern.
In a scenario where you need to process a large array without blocking the event loop, how would a generator function be beneficial?
- Allows asynchronous iteration
- Simplifies event-driven programming
- Enhances parallel processing
- Efficiently manages memory
Generator functions in JavaScript allow asynchronous iteration, which is beneficial in scenarios where you need to process a large array without blocking the event loop. The yield keyword in generators facilitates asynchronous operations, enabling non-blocking code execution.
How does Promise chaining help in handling asynchronous operations?
- It simplifies callback hell by allowing sequential execution of asynchronous tasks.
- It increases the complexity of asynchronous code.
- It only works with synchronous operations.
- It requires additional external libraries.
Promise chaining is a technique that allows sequential execution of asynchronous tasks, making the code more readable and maintainable by avoiding callback hell.