Principal Application Engineer Interview Questions and Answers

To design an application that loads UI fast with many components worked on by multiple teams, focus on optimizing code, utilizing lazy loading, implementing caching mechanisms, and conducting regular performance testing.

• Optimize code by reducing unnecessary dependencies and minimizing the use of heavy libraries

• Implement lazy loading to only load components when they are needed, reducing initial load time

• Utilize caching mechanisms to store frequently accessed data locally, red...read more

Implementing multiple API calls concurrently using asynchronous programming techniques

• Use asynchronous programming techniques such as Promises or async/await in JavaScript to make multiple API calls concurrently

• Create an array of Promises for each API call and use Promise.all() to wait for all calls to finish

• Consider using libraries like Axios or Fetch for making API calls in a more efficient manner

useEffect is a React hook used for handling side effects in functional components.

• useEffect is used to perform side effects in function components, such as data fetching, subscriptions, or manually changing the DOM.

• It runs after every render by default, but you can specify dependencies to control when it runs.

• It can return a cleanup function to clean up any resources created by the effect.

• Example: useEffect(() => { fetchData(); }, [dependency]);

React is a JavaScript library for building user interfaces, while Angular is a full-fledged framework for web development.

• React is more lightweight and flexible compared to Angular.

• Angular is a complete framework with built-in features like routing and state management, while React requires additional libraries for these functionalities.

• React uses a virtual DOM for better performance, while Angular uses a real DOM.

• React follows a unidirectional data flow, while Angular uses a...read more