Harness Senior Front end Developer Interview Questions and Answers

Q1. Closers along with mcq on closers
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Q2. Event loop detailed explanation
Ans. 
Event loop is a mechanism in JavaScript that allows for asynchronous operations to be executed in a non-blocking way.
• Event loop is responsible for handling the execution of code in JavaScript.

• It allows for asynchronous operations to be executed without blocking the main thread.

• Tasks are added to the event queue and executed in the order they were added.

• Event loop continuously checks the call stack and the event queue t
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Normal react counter question, lifecycle method

Q1. What are states and props in React?
Ans. 
States and props are important concepts in React for managing and passing data between components.
• States are mutable data that can be changed within a component

• Props are read-only data passed from parent to child components

• States are managed within a component using setState() method

• Props are accessed using this.props in a component
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Q2. What is Virtual DOM
Ans. 
Virtual DOM is a lightweight copy of the actual DOM that allows for efficient updates and rendering in web applications.
• Virtual DOM is a concept used in frameworks like React to improve performance by minimizing direct manipulation of the actual DOM.

• When changes are made to the virtual DOM, a comparison is done with the actual DOM to determine the minimal updates needed for rendering.

• This process helps reduce the numbe...read more
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Q3. Build a fetch and filter component
Ans. 
A fetch and filter component for data retrieval and manipulation
• Use fetch API to retrieve data from an API endpoint

• Implement a filter function to manipulate the retrieved data based on user input

• Display the filtered data in the UI
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Javascript and React snippets

Q1. Basic components communication
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Q2. Forms based questions
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They asked JS basics and Promises, hoisting

Just asked about my work culture, as I worked in startup and product based company, they except me work in Agile and how u will adopt to MNC / service based company culture

Q1. What is Hositing
Ans. 
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 but not their initializations

• Function declarations are fully hoisted

• Hoisting can lead to unexpected behavior if not understood properly
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Q2. What is closure
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Closure is the combination of a function bundled together with references to its surrounding state.
• Closure allows a function to access variables from its outer scope even after the outer function has finished executing.

• It is created whenever a function is defined within another function.

• Closure helps in maintaining the state of a function and allows for data encapsulation.
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Aptitude round consists Logical reasoning, General Aptitude, Grammar related questions etc. All are moderate level questions.

Q1. Explain OOPs w.r.t Java
Ans. 
OOPs is a programming paradigm that uses objects to represent real-world entities. Java is an OOPs language.
• OOPs stands for Object-Oriented Programming System

• Java is a class-based OOPs language

• Encapsulation, Inheritance, Polymorphism, and Abstraction are the four pillars of OOPs

• Objects have state and behavior

• Java supports interfaces, which allow for multiple inheritance

• Example: A car can be represented as an object wit...read more
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Q2. Explain about the projects that you have worked on
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Q3. Explain how Java solves machine dependency of code execution
Ans. 
Java solves machine dependency by using bytecode and virtual machine.
• Java code is compiled into bytecode which is platform-independent

• The bytecode is executed by the Java Virtual Machine (JVM) which is platform-specific

• JVM translates bytecode into machine code for the specific platform

• This allows Java code to run on any platform with a JVM installed

• Example: A Java program compiled on Windows can run on Linux or Mac as
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Q1. Why should we hire you?
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Q2. Tell me about yourself.
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