To avoid blocking the event loop when processing large arrays, you might implement a "for" loop with a technique called ________.
- multithreading
- event delegation
- Web Workers
- callback functions
To avoid blocking the event loop when processing large arrays, you might implement a "for" loop with a technique called Web Workers. Web Workers allow you to run JavaScript code in the background, off the main thread, and can be used for parallel processing, making them suitable for tasks like processing large arrays without freezing the UI.
When you want to iterate over the values of an object’s properties, instead of the property names, you can use the ________ loop.
- for...in
- for...of
- while
- forEach
When you want to iterate over the values of an object's properties, instead of the property names, you can use the for...of loop. This loop is specifically designed for iterating over iterable objects, such as arrays and the values of iterable properties in objects, providing a more concise way to access values.
JavaScript was originally developed under the name _________.
- LiveScript
- WebScript
- CodeScript
- MochaScript
JavaScript was originally developed under the name "LiveScript." It was later renamed to "JavaScript" to leverage the popularity of Java. The choice of the name "LiveScript" was mainly a marketing decision at the time.
To check for equality without considering the type in JavaScript, you should use ______.
- === (Triple Equals)
- == (Double Equals)
- #NAME?
- !== (Not Equals)
In JavaScript, the "===" operator, known as the triple equals operator, is used to check for equality without considering the data types of the operands. It ensures both the value and the type of the operands are identical.
What challenge is commonly associated with callback functions in asynchronous JavaScript?
- Synchronous execution
- Callback hell
- Memory leaks
- Variable scope
Callback hell is a common challenge in asynchronous JavaScript. It occurs when you have multiple nested callbacks, making the code hard to read and maintain. This situation can lead to callback hell, where code becomes difficult to manage and understand.
How can the issues related to memory leaks due to closures be mitigated in JavaScript?
- Using WeakMaps
- Increasing Closure Scope
- Avoiding Closures
- Garbage Collection
Memory leaks due to closures can be mitigated by using WeakMaps in JavaScript. WeakMaps are a data structure that allows objects to be held weakly, meaning they won't prevent objects from being garbage collected. This helps in preventing memory leaks that can occur when closures hold references to objects longer than necessary.
When different classes have methods of the same name, this is referred to as method _________.
- overriding
- overloading
- overloading
- overriding
When different classes have methods of the same name with different parameters, this is referred to as "method overloading." Method overloading allows a class to have multiple methods with the same name but different parameter lists.
How might the use of immediately-invoked function expressions (IIFE) impact the performance of a JavaScript application?
- IIFE can significantly improve performance by reducing global variable usage.
- IIFE has no impact on performance; it's purely a coding style choice.
- IIFE can slow down performance due to excessive function calls.
- IIFE can lead to memory leaks in JavaScript applications.
The use of IIFE in JavaScript can have a positive impact on performance. By encapsulating code within an IIFE, you reduce the use of global variables, which can lead to fewer naming conflicts and better performance. IIFE is commonly used for encapsulating code safely and efficiently. It's not a performance bottleneck but rather a coding pattern for better code organization.
You're writing a function that removes an element from an array without mutating the original array and returns the new array. Which array method could help you achieve this?
- filter()
- splice()
- pop()
- push()
The filter() method creates a new array with all elements that pass the test implemented by the provided function, making it a suitable choice for removing elements from an array without changing the original array. The splice() method can be used for removing elements but mutates the original array. pop() and push() are used for adding/removing elements from the end of an array.
In a switch statement, if the break keyword is not used, it results in _________.
- An error
- A warning
- Fall-through behavior
- A timeout
In a switch statement, if the break keyword is not used, it results in fall-through behavior. Fall-through means that once a case is matched and its code block is executed, the program continues to execute the code blocks of subsequent cases, even if they don't match. This can lead to unintended behavior and is usually controlled by using the break keyword.