Deloitte Senior Front end Developer Interview Questions and Answers

Implementing pagination on scroll allows for loading more content as the user reaches the bottom of the page.

• Use a scroll event listener to detect when the user has reached the bottom of the page

• Make an API call to fetch more data when the bottom is reached

• Append the new data to the existing content on the page

Immediately invoked function expressions (IIFE) are functions that are executed immediately after they are created.

• IIFE is defined and invoked at the same time using parentheses at the end of the function declaration.

• Anonymous functions do not have a name and can be used as IIFE by wrapping them in parentheses.

• IIFE is commonly used to create a private scope for variables and functions.

Closures are functions that have access to variables from their outer scope even after the outer function has finished executing.

• Closures allow functions to access variables from their parent function even after the parent function has returned

• They help in creating private variables and functions in JavaScript

• Closures are commonly used in event handlers and callbacks

A promise is an object representing the eventual completion or failure of an asynchronous operation.

• Promises are used to handle asynchronous operations in JavaScript.

• They can be in one of three states: pending, fulfilled, or rejected.

• Promises can be chained using .then() method to handle success and failure callbacks.

• Example: Fetch API returns a promise when making an HTTP request.

Lazy loading is a technique used in web development to defer loading non-essential resources until they are needed.

• Lazy loading helps improve page load times by only loading resources when they are required.

• It is commonly used for images, videos, and other media files on a webpage.

• Lazy loading can be implemented using JavaScript libraries like Intersection Observer or by using native browser features like loading='lazy...read more

I began my journey in web development, evolving from basic HTML to advanced frameworks, honing my skills in JavaScript and UI design.

• Started with HTML and CSS, creating static websites for local businesses.

• Learned JavaScript to add interactivity, building a personal project like a weather app using APIs.

• Explored frameworks like React and Vue.js, developing a complex e-commerce site with React.

• Gained experience in respo...read more

Angular is a powerful front-end framework for building dynamic web applications using TypeScript and component-based architecture.

• Component-based architecture: I have created reusable components for UI elements, such as buttons and modals, enhancing maintainability.

• Dependency Injection: Utilized Angular's DI system to manage services, making it easier to share data and functionality across components.

• Routing: Implement...read more

I have used various features of HTML including semantic elements, forms, multimedia, and canvas.

• Semantic elements like <header>, <footer>, <nav>, <article>, <section>

• Forms with input types like text, email, password, radio buttons, checkboxes, and submit buttons

• Multimedia elements like <img>, <audio>, <video>

• Canvas for drawing graphics and animations

Flex in CSS is a layout module that allows elements to align and distribute space within a container.

• Flexbox is used for creating flexible and responsive layouts.

• It allows for easy alignment and distribution of elements within a container.

• Flex properties include flex-direction, justify-content, align-items, and flex-grow.

Flex is a CSS layout model that allows responsive and flexible design. Hoisting is a JavaScript behavior where variable and function declarations are moved to the top of their scope. Function expressions are anonymous functions assigned to variables.

• Flex is used for creating responsive and flexible layouts in CSS.

• Hoisting in JavaScript moves variable and function declarations to the top of their scope.

• Function expressi...read more