Accenture React Js Frontend Developer Interview Questions, Process, and Tips

Prop drilling is the process of passing props down multiple levels of nested components in React.

• Prop drilling occurs when a prop needs to be passed through multiple levels of components that do not need the prop themselves.

• It can lead to unnecessary passing of props through intermediate components, making the code harder to maintain.

• To avoid prop drilling, you can use Context API, Redux, or React's useContext and useR...read more

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during the compilation phase.

• Variable declarations are hoisted to the top of their scope, but not their assignments.

• Function declarations are fully hoisted, meaning they can be called before they are declared.

• Hoisting can lead to unexpected behavior if not understood properly.

useContext hook allows components to access data from a context without passing props down manually

• useContext hook is used to consume a context created by React.createContext

• It takes the context object as an argument and returns the current context value for that context

• It allows components to subscribe to context changes and re-render when the context value changes

React Query is a library for managing server state in React applications, while Redux is a state management library for managing client-side state.

• React Query is specifically designed for managing server state, making it easier to fetch, cache, and update data from APIs.

• Redux is a more general-purpose state management library that can be used for managing client-side state in a predictable way.

• React Query provides buil...read more

Interface is for defining object shapes and types, while type is for creating aliases for existing types.

• Interface is used for defining the structure of an object in TypeScript.

• Type is used to create aliases for existing types, making code more readable and reusable.

• Interfaces can be extended or implemented, while types can be used to create union types or intersection types.

• Interfaces are open for extension, while typ

useState() is a React Hook that allows functional components to manage state.

• useState() is imported from React: `import React, { useState } from 'react';`

• It returns an array with two elements: the current state and a function to update it.

• Example: `const [count, setCount] = useState(0);` initializes count to 0.

• The state can be updated by calling the updater function: `setCount(count + 1);`.

• useState() can hold any data

React JS offers a component-based architecture, efficient rendering, and a strong community, making it ideal for modern web development.

• Component-Based Architecture: React allows developers to build encapsulated components that manage their own state, making code reusable and easier to maintain.

• Virtual DOM: React uses a virtual representation of the DOM to optimize rendering, resulting in faster updates and improved pe...read more

React JS has limitations such as performance issues, SEO challenges, and a steep learning curve for beginners.

• Performance: Large applications can lead to performance bottlenecks if not optimized properly. For example, excessive re-renders can slow down the app.

• SEO Challenges: React applications can have issues with search engine optimization since content is rendered on the client-side. Server-side rendering (SSR) can ...read more

Keys in React are unique identifiers for elements in lists, helping React optimize rendering and manage component updates efficiently.

• Keys help React identify which items have changed, are added, or are removed.

• They should be unique among siblings but can be reused in different lists.

• Using indexes as keys can lead to issues with component state and performance.

• Example: <li key={item.id}>{item.name}</li> in

JSX is a syntax extension for JavaScript that allows writing HTML-like code within JavaScript, primarily used in React.

• JSX stands for JavaScript XML.

• It allows developers to write HTML structures in the same file as JavaScript code.

• JSX is transpiled to JavaScript using tools like Babel.

• Example: <h1>Hello, World!</h1> becomes React.createElement('h1', null, 'Hello, World!').

• JSX can also embed JavaScript expre...read more

Functional components are simpler and use hooks, while class components manage state and lifecycle methods.

• Functional components are stateless and simpler, while class components can manage state and lifecycle methods.

• Functional components use hooks (e.g., useState, useEffect) for state and side effects, whereas class components use 'this.state' and 'this.setState'.

• Class components require 'render()' method to return J...read more

Virtual DOM is a lightweight copy of the actual DOM that React uses to improve performance by minimizing direct manipulation of the actual DOM.

• Virtual DOM is a representation of the actual DOM in the form of a lightweight copy.

• When changes are made to the virtual DOM, React compares it with the actual DOM to identify the minimal number of changes needed.

• This process helps in optimizing performance by reducing direct ma...read more

Reconciliation in React is the process of updating the DOM to match the virtual DOM.

• Reconciliation is the algorithm that React uses to update the UI efficiently.

• It compares the virtual DOM with the previous virtual DOM and only updates the necessary components.

• Reconciliation helps in improving performance by minimizing DOM manipulations.

• Key prop is important for reconciliation to identify which items have changed, adde...read more

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's scope

• They maintain a reference to the variables they need, even after the parent function has finished executing

• Closures are commonly used in event handlers and callbacks

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during compilation.

• Hoisting applies to both variable and function declarations.

• Variable declarations are hoisted to the top of their scope but not their assignments.

• Function declarations are fully hoisted, meaning they can be called before they are declared.

ES6 features are modern JavaScript syntax enhancements that make code more concise and readable.

• Arrow functions for more concise syntax: const add = (a, b) => a + b;

• Let and const for block-scoped variables: let x = 5; const y = 10;

• Template literals for string interpolation: const name = 'Alice'; console.log(`Hello, ${name}!`);

• Destructuring assignment for easily extracting values from objects or arrays: const { firstNam...read more

React Fiber is a complete rewrite of React's core algorithm for rendering UI components.

• React Fiber is a reimplementation of the React core algorithm.

• It allows for incremental rendering, prioritizing updates based on their priority level.

• Fiber reconciles the virtual DOM tree in a more efficient and flexible way.

• It enables features like error boundaries, async rendering, and more.

• Fiber was introduced in React version 16

Implementing dark mode in an application involves changing the color scheme to darker tones for better visibility in low light environments.

• Use CSS variables to define color schemes for light and dark modes

• Toggle between light and dark mode using a state variable in React

• Apply the appropriate color scheme based on the selected mode

• Allow users to switch between light and dark mode using a toggle button