Techsteck Solutions Front end Developer Interview Questions and Answers

Q1. JavaScript Related Questions
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Q2. ReactJs Related Questions
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Q1. Reactjs Use Effects and UseRef
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Q2. JavaScript Closures,Map,CallBack
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Coding a frontend UI from provided image. And creating a fucntional star rating system

Q1. Designing a Component API in React using Typescript.
Ans. 
Designing a Component API in React using Typescript involves defining props, state, and methods for the component.
• Define the props interface to specify the expected input data for the component

• Use typescript types to ensure type safety and prevent runtime errors

• Define the state interface to manage the internal state of the component

• Implement methods to handle user interactions and component logic

• Document the component
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Q2. Create a function that can clear all the timer ids at once.
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Function to clear all timer ids at once
• Create an array to store all timer ids

• Iterate through the array and clear each timer id using clearTimeout() function
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Q1. Let var const in JavaScript
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var and const are used to declare variables in JavaScript, with var being mutable and const being immutable.
• var is used to declare variables that can be reassigned and updated

• const is used to declare variables that cannot be reassigned or updated

• let is another keyword used for declaring variables, similar to var but with block scope
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Q2. Error boundary and how to handle
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Error boundary is a React component that catches JavaScript errors anywhere in a component tree and logs those errors.
• Error boundaries are React components that catch JavaScript errors in their child component tree.

• They are used to prevent the entire UI from crashing due to a single error.

• Error boundaries work like a JavaScript catch {} block, but for components.

• They are defined using componentDidCatch lifecycle method
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Q3. Event.bind and event.property
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Q4. Use of never in typescript
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The 'never' type in TypeScript represents a value that will never occur.
• Used to indicate that a function will not return a value

• Commonly used in union types to exclude certain values

• Helps catch potential errors at compile time
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Q5. What hooks you have used
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I have used React hooks such as useState, useEffect, useContext, and useRef in my projects.
• useState

• useEffect

• useContext

• useRef
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Q6. What is difference between use reducer and use state
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useReducer is preferred for managing complex state logic, while useState is simpler for basic state management.
• useReducer is more suitable for managing complex state logic and multiple state values

• useState is simpler and more straightforward for basic state management with a single value

• useReducer allows for more organized and centralized state updates through actions and reducers

• useState is commonly used for simple co
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Q7. Why we use state and props
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Q8. How you will pass data from parent to child
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Data can be passed from parent to child components in React using props.
• Pass data as props from parent component to child component

• Use state management libraries like Redux or Context API for complex data sharing

• Use callback functions to pass data from child to parent components
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Q9. Write your own custom hook
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Custom hook to fetch data from an API
• Create a function that uses the useState and useEffect hooks

• Use the fetch API to make a request to the desired endpoint

• Return the fetched data and loading state in an array
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Q10. Explain map filter and reduce functions
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Map, filter, and reduce are higher-order functions in JavaScript used to manipulate arrays.
• Map: Transforms each element in an array and returns a new array with the transformed elements.

• Example: [1, 2, 3].map(num => num * 2) returns [2, 4, 6].

• Filter: Returns a new array with elements that pass a certain condition.

• Example: [1, 2, 3].filter(num => num > 1) returns [2, 3].

• Reduce: Applies a function against an accumulator ...read more
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Q11. How you can clone an object
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To clone an object in JavaScript, you can use the spread operator or Object.assign() method.
• Use the spread operator to create a shallow copy of an object: const clonedObj = { ...originalObj };

• Use Object.assign() method to create a shallow copy of an object: const clonedObj = Object.assign({}, originalObj);

• For deep cloning, you can use libraries like Lodash or write a custom function to recursively clone nested objects.
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Q12. What are the three stages of event propagation and how to handle it
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Event propagation consists of three stages: capturing, target, and bubbling.
• Capturing phase: Events are captured from the outermost element to the target element.

• Target phase: Event reaches the target element where the event originated.

• Bubbling phase: Events bubble up from the target element to the outermost element.
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Q13. How to handle errors in your react application
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Errors in a React application can be handled by using error boundaries, try-catch blocks, and displaying error messages to users.
• Use error boundaries to catch errors in components and display a fallback UI

• Wrap code that may throw errors in try-catch blocks to handle exceptions

• Use libraries like React Error Boundary to easily implement error handling

• Display error messages to users to inform them about the issue and poss
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Q14. Write code to call fake api and display the title where category is “some category “
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Q1. It was a array question. I was told to return a object from a function which would contain getting all the array elements, adding a element, deleting a element. The test was on hacker rank.
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Q1. This was basically a one on one round. I was asked basics of HTML, CSS and React. Questions like Hoisting, Prop Drilling, Context API. Not only do you need to know what the topics are. But I was asked to i...read more
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Q1. Basic Company Details and Salary Negotiations
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Find reverse string using array

Q1. What are Routing Guards?
Ans. 
Routing guards are used in Angular to control access to certain routes based on certain conditions.
• Routing guards are used to protect routes in Angular applications.

• They can be used to control access based on authentication status, user roles, etc.

• There are different types of routing guards like CanActivate, CanActivateChild, CanDeactivate, CanLoad.

• Example: CanActivate guard can be used to check if a user is authentica
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Q1. What is react and it's advantage
Ans. 
React is a JavaScript library for building user interfaces.
• React allows for the creation of reusable UI components

• It uses a virtual DOM for efficient rendering

• React is declarative, making it easier to understand and debug code
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Q2. React life cycle
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Q3. Questions related to Redux
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Q4. Simple app using redux
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Creating a simple app using Redux for state management in a front end application.
• Set up Redux store with reducers and actions

• Connect components to Redux store using mapStateToProps and mapDispatchToProps

• Dispatch actions to update state in Redux store

• Use combineReducers to manage multiple reducers
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Q1. Previous project
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Q2. Agile process followed in project
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Agile process involves iterative development, frequent collaboration, and adaptability to changes.
• Daily stand-up meetings to discuss progress and roadblocks

• Sprints for focused development and testing

• Continuous feedback and iteration based on user input

• Use of tools like Jira or Trello for project management
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Q1. Salary discussion
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Q2. Work location discussion
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Q1. What is aptitude
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Q2. Front end developer in how much are there
Ans. 
Front end developers are in high demand due to the increasing importance of user experience in web development.
• Front end developers work on the client side of web development, focusing on the user interface and user experience.

• They are responsible for implementing designs, optimizing performance, and ensuring cross-browser compatibility.

• Front end developers often use HTML, CSS, and JavaScript, as well as frameworks lik...read more
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Q3. 3 or 4 maximum that's it
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Q4. What isreasoning
Ans. 
Reasoning is the mental process of thinking, understanding, and forming conclusions.
• Reasoning involves using logic and critical thinking to make sense of information.

• It helps in problem-solving and decision-making by analyzing and evaluating evidence.

• Types of reasoning include inductive reasoning, deductive reasoning, and abductive reasoning.
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Q5. How to get success interview
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Q1. What is mean by dom
Ans. 
DOM stands for Document Object Model, which is a programming interface for web documents.
• DOM is a representation of the structure of a web page, allowing scripts to dynamically access and update the content, structure, and style of the page.

• It provides a way for scripts to interact with the elements on a web page, such as changing text, styles, and attributes.

• DOM is hierarchical, with elements nested inside other eleme...read more
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Q2. Explain promise in typescript
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Promises in TypeScript are objects representing the eventual completion or failure of an asynchronous operation.
• Promises are used to handle asynchronous operations in a more readable and manageable way.

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

• Promises can be chained using .then() to handle success and .catch() to handle errors.

• Example: const myPromise = new Promise((resolve, reject) => { ...
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Q3. Explain hooks in javascript
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Hooks in JavaScript are functions that let you use state and other React features without writing a class.
• Hooks were introduced in React 16.8 to allow functional components to have state and lifecycle methods.

• useState() is a hook that allows you to add state to functional components.

• useEffect() is a hook that allows you to perform side effects in functional components.

• Custom hooks are functions that allow you to reuse
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Q4. Write a program 1 to 100 prime numbers
Ans. 
Generate an array of prime numbers from 1 to 100.
• Iterate from 1 to 100 and check if each number is prime

• A prime number is only divisible by 1 and itself

• Start with a list of prime numbers and check divisibility
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