What is the difference between synchronous and asynchronous JavaScript?
Answer: Synchronous JavaScript executes code sequentially, blocking further execution until the task is completed, while asynchronous JavaScript allows tasks to be executed independently, without blocking other operations.
How can you handle cross-origin requests in JavaScript?
Answer: Cross-Origin Resource Sharing (CORS) can be handled by the server sending appropriate CORS headers to indicate which origins are allowed to access its resources.
Explain the concept of Promises in JavaScript.
Answer: Promises are objects used for handling asynchronous operations in JavaScript, representing a future value that may resolve to a result or an error.
Describe the role of the "use strict" directive in JavaScript.
Answer: The "use strict" directive enables strict mode, enforcing modern JavaScript best practices and preventing certain error-prone behaviors.
How do you optimize the rendering performance of a React application?
Answer: Optimizing rendering performance involves using techniques like memoization, PureComponent, and React's memo to reduce unnecessary re-renders.
What is a Higher-Order Component (HOC) in React?
Answer: HOC is a design pattern in React that allows you to wrap a component with additional functionality by returning a new component.
How can you improve the Search Engine Optimization (SEO) of a Single Page Application (SPA)?
Answer: Implement server-side rendering (SSR) or use techniques like pre-rendering and dynamic rendering to improve SEO for SPAs.
Explain the role of the Fetch API in modern web development.
Answer: The Fetch API provides a native way to make HTTP requests in JavaScript, offering a more modern and flexible alternative to XMLHttpRequest.
Describe the concept of Code Splitting and its benefits in web applications.
Answer: Code Splitting is a technique used to split a large JavaScript bundle into smaller chunks, improving initial loading times and reducing bandwidth usage.
How can you optimize the performance of CSS animations and transitions?
Answer: Optimizations include using hardware-accelerated properties like "transform" and "opacity," minimizing the use of expensive properties like "box-shadow," and avoiding excessive nesting in animations.