To execute multiple async functions in parallel and wait for all of them, use __________.
- Promise.all()
- Promise.race()
- Promise.parallel()
- Promise.sequence()
To execute multiple asynchronous functions concurrently and wait for all of them to complete, the appropriate method is Promise.all(). It takes an array of promises and resolves when all the promises in the array have resolved. Promise.race() would resolve as soon as any of the promises in the array resolves, which might not be suitable for waiting for all of them. Understanding the correct usage of Promise.all() is crucial for efficient handling of parallel asynchronous tasks.
How does the static structure of ES6 Modules aid in tree shaking compared to CommonJS?
- Easier debugging due to explicit dependencies
- Improved dead code elimination
- Faster runtime performance
- Better support for dynamic imports
ES6 Modules have a static structure, allowing tools to analyze dependencies at build time. Tree shaking is the process of eliminating dead code, and ES6 Modules excel in this regard, making it easier to eliminate unused code during bundling.
In ES6, how does the shorthand for method properties affect the 'function' keyword in object literals?
- It removes the need for the 'function' keyword.
- It enforces the use of the 'function' keyword.
- It modifies the behavior of the 'function' keyword.
- It's not related to the 'function' keyword.
In ES6, the shorthand for method properties allows omitting the 'function' keyword when defining methods in object literals. It enhances code readability by providing a more concise syntax for method definitions within objects. This syntactic sugar simplifies the declaration of methods in objects, making the code cleaner and more modern.
The concept of ________ is essential in understanding how functions are combined in functional composition.
- Closure
- Immutability
- Prototypes
- Referential transparency
The concept of referential transparency is essential in understanding how functions are combined in functional composition. Referential transparency means that a function, given the same inputs, will always return the same output, allowing for easier reasoning about the behavior of composed functions.
Consider a function that fetches user data from an API. How can this function be refactored to adhere to the principles of pure functions?
- Return the fetched data directly
- Introduce a callback for data processing
- Include a random delay in fetching data
- Use global variables for storing the fetched data
To make the function pure, it should return the fetched data directly without relying on external state or global variables. Introducing a callback or using global variables can introduce side effects, which contradicts the principles of pure functions.
In a scenario where dynamic property names are based on user input, how would ES6 object literals be utilized?
- Utilize computed property names to dynamically assign properties
- Utilize the Object.assign method for dynamic property assignment
- Use Object.create for dynamic property generation
- Implement a switch statement for dynamic property naming
ES6 object literals allow the use of computed property names, which is particularly beneficial in scenarios where dynamic property names are based on user input. Computed property names enable the creation of object properties dynamically based on expressions, providing flexibility and conciseness in handling user input.
Using await inside a __________ loop can cause asynchronous operations to run sequentially.
- for
- while
- do-while
- foreach
When using await inside a loop, such as a while loop, it may lead to unexpected behavior. This is because the loop will not pause for each asynchronous operation to complete before moving to the next iteration, potentially causing them to run sequentially. It's crucial to understand the implications of using await inside loops and consider alternative approaches for parallel execution of asynchronous operations.
To use destructuring in a for...of loop iterating over a Map, you would write for (const [key, ______] of map).
- item
- val
- value
- element
To use destructuring in a for...of loop iterating over a Map, you would write for (const [key, value] of map). The value here is the second element of the destructuring assignment, representing the value associated with the current key in the Map.
Each call to the next() method on a generator returns an object with two properties: value and _________.
- result
- done
- output
- complete
The next() method on a generator returns an object with two properties: value (the yielded value) and done (a boolean indicating whether the generator has completed). The other options do not represent the properties returned by the next() method.
Imagine you are creating a gaming application with different types of characters. How would you use inheritance in ES6 classes to implement shared behaviors?
- Object Composition
- Using Mixins
- Extending Base Class
- Function Constructors
In this scenario, you would extend a base class to create subclasses for each character type. Option A is about combining objects, Option B is about sharing functionality through mixins, and Option D is an older approach not commonly used in ES6.