Frontend Interview Quiz Part 2

When creating methods inside a constructor in JavaScript, you can use either the traditional function syntax or the arrow function syntax. The advantage of using arrow functions in a constructor is that they allow access to the "this" keyword of the parent scope, which is not possible with traditional functions. This is because arrow functions do not create their own "this" context, but instead inherit it from the surrounding scope. This can be useful when you need to reference the parent object's properties or methods within the method. However, it's important to note that arrow functions are not suitable for all use cases and traditional functions should still be used in some scenarios.

Layout, painting, and compositing are all important steps in the process of rendering a web page on the screen.

Layout is the process of defining the size, position, and arrangement of elements on the page, using tools like HTML, CSS, and JavaScript. This includes determining the size and position of boxes, the placement of text and images, and the overall flow and structure of the page.

Painting is the process of rendering the visual properties of those elements onto the screen, including things like color, texture, and typography. This involves converting the layout information into pixels that can be displayed on the screen, and may involve additional processes like anti-aliasing or blending.

Compositing is the process of combining multiple layers of elements into a final image that is displayed on the screen. This includes managing the z-order of elements, applying transparency and blending effects, and optimizing performance to ensure smooth and efficient rendering.

Understanding the differences between layout, painting, and compositing can be helpful for developers and designers who are optimizing web page performance or troubleshooting display issues, as each step in the process can have its own unique challenges and considerations.

The difference between "nth-of-type()" and "nth-child()" selectors is that "nth-of-type()" selects only elements of a specific type, such as <p> or <div>, based on their position in the parent element, while "nth-child()" selects all children of a parent element, regardless of their type, based on their position. For example, "nth-of-type(2)" would select the second <p> element within a parent element, while "nth-child(2)" would select the second child element of any type within the parent element.

In JavaScript, synchronous functions block the execution of code until they complete. This means that when a synchronous function is called, the program will pause and wait for the function to finish executing before continuing to the next line of code. Synchronous functions can cause the program to become unresponsive if they take a long time to execute.

On the other hand, asynchronous functions do not block the execution of code. Instead, they execute in the background and notify the program when they are finished, usually by using a callback function or a promise. This allows the program to continue executing other code while the asynchronous function is running, making it more responsive and efficient.

Synchronous and asynchronous functions are different in their behavior and how they are executed in the program. Synchronous functions block the execution of code until they complete, while asynchronous functions allow the program to continue executing while they are running.

CSS Grid and Flexbox are both powerful layout tools in CSS, but they serve different purposes. CSS Grid is used for two-dimensional layouts, meaning layouts that have both rows and columns. This allows for more complex and flexible layouts, where elements can be placed in any cell or span across multiple cells. Flexbox, on the other hand, is used for one-dimensional layouts, meaning layouts that have either rows or columns, but not both. Flexbox is especially useful for aligning and distributing items along a single axis, such as horizontally or vertically. While both CSS Grid and Flexbox can be used for some similar layout tasks, understanding their differences and intended use cases can help developers choose the appropriate tool for the job.

A promise in JavaScript is an object that represents a value that may not be available yet, but will be resolved in the future. It allows us to write asynchronous code in a more readable and manageable way. A promise has three states: pending (initial state), fulfilled (resolved with a value), and rejected (resolved with a reason for failure). Once a promise is fulfilled or rejected, it stays in that state and cannot be changed. Promises can be chained together using then() method to handle success or catch() method to handle failures.

The title attribute is a common HTML attribute used to provide additional information about an element, such as a link or an image. When a user hovers over the element, the content of the title attribute is typically displayed as a tooltip or hint. This tooltip or hint is also exposed to assistive technologies, such as screen readers, which can read the content of the title attribute aloud to users who may not be able to see it. This is why it's important to use descriptive and meaningful content in the title attribute, as it can help provide additional context and information to users who may need it.

The accessibility tree is a data structure used by web browsers to represent the structure of a web page in a way that is compatible with assistive technologies, such as screen readers. It provides a way for these technologies to access and understand the content and structure of the page, including elements like headings, links, and form fields. The accessibility tree is created based on the underlying HTML and CSS of the page, but it also takes into account any changes made to the page through JavaScript or other client-side technologies. By ensuring that the accessibility tree is properly constructed and up-to-date, developers can help ensure that their web pages are accessible to users with a wide range of disabilities.

A focus trap is a programming technique that prevents users from tabbing out of a modal dialog box, also known as a "modal window" or "modal overlay". Modal dialogs are a common design pattern used in user interfaces to display important messages or prompts, but they can be frustrating for users if they can't navigate away from them using keyboard shortcuts or tabbing. A focus trap ensures that the user's focus remains within the dialog box until they have completed the required action, such as filling out a form or making a selection, and then allows them to exit the dialog box.

Skip links are links that allow users to skip over blocks of content on a web page that may be repetitive or irrelevant, such as navigation menus, banner ads, or other content that appears on multiple pages. Skip links are typically hidden from view until they are focused by the keyboard or screen reader, at which point they become visible and can be activated by the user.

Skip links are especially useful for users who navigate the web using assistive technologies, such as screen readers, as they allow them to quickly jump to the main content of a page without having to listen to every element on the page. Skip links can also benefit users with motor impairments, who may find it difficult or time-consuming to navigate through a large number of links or controls before reaching the main content of a page.

Implementing skip links is considered a best practice for web accessibility, as it can help improve the user experience for a wide range of users, regardless of their abilities or preferences.

In JavaScript, the call stack is a data structure that keeps track of the order in which functions are executed. When a function is called, it is added to the top of the call stack, and when it finishes executing, it is removed from the stack. This allows JavaScript to execute functions in the order they were called, and ensures that the correct function is executed at the correct time.

The task queue, on the other hand, is where asynchronous tasks are queued for later execution. When an asynchronous task, such as a timer or an event listener, is triggered, it is added to the task queue. The task queue waits until the call stack is empty, and then adds the next task from the queue to the call stack for execution.

The call stack and the task queue are different data structures that serve different purposes in JavaScript. The call stack is used to keep track of the order in which functions are executed, while the task queue is used to queue asynchronous tasks for later execution.

Carousels, also known as sliders or slideshows, are a common design pattern used on many websites and applications to showcase multiple pieces of content in a compact space. However, they can present a number of accessibility challenges for users with disabilities.

For users with certain visual impairments, the motion and speed of a carousel can cause discomfort, nausea, or even seizures. This can be especially problematic for users with vestibular disorders or other conditions that affect their sense of balance and orientation.

For users with motor impairments, carousels can be difficult or impossible to navigate using a mouse, keyboard, or other input device. This can be due to a number of factors, such as the small size of the carousel buttons, the speed at which the carousel rotates, or the lack of keyboard support for moving between carousel items.

For users with cognitive disabilities, carousels can present information too quickly for them to process and understand. This can be especially problematic if the carousel is being used to convey important or time-sensitive information, such as a product promotion or a news headline.

To address these accessibility challenges, designers and developers can consider alternative design patterns, such as static image galleries or simple lists, or provide options for users to pause or control the speed of the carousel. Additionally, ensuring that carousels are properly marked up with appropriate ARIA attributes and keyboard support can also improve accessibility for users with disabilities.

The while loop in JavaScript executes its code block only if the condition specified in the loop header is true. It first checks the condition and then executes the code block. If the condition is false, the loop will not execute. On the other hand, the do-while loop executes its code block at least once, regardless of whether the condition specified in the loop header is true or false. It first executes the code block, and then checks the condition at the end of each iteration. If the condition is true, the loop continues to execute. If the condition is false, the loop terminates. Do-while loops are useful in situations where you need to ensure that a piece of code is executed at least once, regardless of the condition.

Landmark regions, also known as ARIA landmarks, are specific regions of a web page that are marked up with HTML attributes to provide accessibility information to screen readers. These regions are used to group together related content, such as the main content area, navigation, and footer. They are defined using the ARIA landmark roles, which include "banner", "complementary", "contentinfo", "form", "main", "navigation", and "region".

By using landmark regions in web pages, web developers can improve accessibility for users with disabilities, such as visual impairments. Screen readers can use the landmark regions to navigate the page and provide context to the user. Landmark regions are an important part of accessible web design and should be used whenever possible.

A higher-order function in JavaScript is a function that takes another function as an argument or returns a function as its result. This means that the function either accepts a function as one of its arguments or returns a new function as its output. Higher-order functions are useful for abstracting away common functionality and making code more reusable. Examples of higher-order functions in JavaScript include Array.prototype.map(), which takes a function as an argument to map each element of an array to a new value, and Function.prototype.bind(), which returns a new function with a fixed "this" value and pre-filled arguments.