AIT Global Node JS Developer Interview Questions and Answers

Q1. How do you handle debugging in your code?
Ans. 
I use print statements, logging, and debugging tools to identify and fix issues in my code.
• I start by reviewing the code and understanding the logic behind it.

• I use print statements to check the values of variables at different points in the code.

• I utilize logging to track the flow of the program and identify any errors.

• I use debugging tools like breakpoints and step-through debugging to pinpoint the exact location of ...read more
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Q2. What is your approach to optimizing a slow-running application?
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Identify bottlenecks, analyze code, optimize algorithms, utilize caching, and consider hardware upgrades.
• Identify bottlenecks in the application by profiling and monitoring performance.

• Analyze the code to find inefficient algorithms or database queries.

• Optimize algorithms and data structures to improve efficiency.

• Utilize caching mechanisms to reduce redundant computations.

• Consider hardware upgrades such as increasing m
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Q3. What is the difference between functional and object-oriented programming?
Ans. 
Functional programming focuses on functions and immutability, while object-oriented programming focuses on objects and encapsulation.
• Functional programming uses pure functions that do not have side effects.

• Object-oriented programming uses objects that encapsulate data and behavior.

• In functional programming, data is immutable and functions are first-class citizens.

• In object-oriented programming, objects can have state a...read more
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Q1. Write a function to find the first non-repeating character in a string ?
Ans. 
Function to find the first non-repeating character in a string
• Create a hashmap to store character frequencies

• Iterate through the string to populate the hashmap

• Iterate through the string again to find the first non-repeating character
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Q2. Explain the difference between a stack and a queue . Provide an example of when you would use each?
Ans. 
A stack is a data structure that follows the Last In First Out (LIFO) principle, while a queue follows the First In First Out (FIFO) principle.
• Stack: Last In First Out (LIFO), used for function calls, undo operations.

• Queue: First In First Out (FIFO), used for printing tasks, message queues.
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It is easy to solve the Aptitude question and some identifying outputs of program.

Q1. What is class?and write a logic for object in a class.
Ans. 
A class is a blueprint for creating objects in object-oriented programming.
• A class defines the properties and behaviors of objects.

• An object is an instance of a class.

• Example: Class 'Car' can have properties like 'color' and 'model', and behaviors like 'drive' and 'stop'.
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Q2. 1.swap two numbers without using temp variable 2.Reverse the string.
Ans. 
Swap two numbers without using temp variable and reverse a string without using built-in functions.
• To swap two numbers without using temp variable, use bitwise XOR operation.

• To reverse a string without using built-in functions, use two pointers approach.

• Example for swapping numbers: a = a ^ b; b = a ^ b; a = a ^ b;

• Example for reversing a string: use two pointers to swap characters from start and end of the string.
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Now, I am preparing for the third round.
So, I don't know the Coding Question.

Q1. How node js works
Ans. 
Node.js is a JavaScript runtime that executes code outside a browser, enabling server-side development with non-blocking I/O.
• Node.js uses an event-driven, non-blocking I/O model, making it efficient for handling multiple connections simultaneously.

• It runs on the V8 JavaScript engine, which compiles JavaScript to native machine code for faster execution.

• Node.js operates on a single-threaded event loop, allowing it to ma...read more
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Q2. What is event loop
Ans. 
The event loop is a core component of Node.js that enables non-blocking I/O operations by managing asynchronous callbacks.
• The event loop allows Node.js to perform non-blocking operations despite being single-threaded.

• It continuously checks the call stack and the message queue to execute tasks.

• When an asynchronous operation completes, its callback is pushed to the message queue.

• The event loop processes the message queue...read more
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Q1. Explaining resume
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Q2. Coding question to print dates of saturday and sunday from month of given input date
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Give 10 questions from node js backend

Q1. Ask about angular and node js
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Q2. What is package.json
Ans. 
package.json is a file used in Node.js projects to manage dependencies, scripts, and metadata.
• It is a JSON file that contains information about the project, such as name, version, dependencies, and scripts.

• It is used to manage project dependencies by listing them in the 'dependencies' and 'devDependencies' fields.

• It allows developers to define scripts for tasks like building, testing, and running the project.

• Example: {...read more
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Q3. What is components in angular,how share data to component
Ans. 
Components in Angular are building blocks of an application. Data can be shared between components using input properties and output events.
• Components in Angular are reusable, self-contained units of code that define a part of the user interface.

• Data can be shared to a component using input properties, where data is passed from the parent component to the child component.

• Data can also be shared from a child component t...read more
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Q4. What is === and == ,and wher use === is real time projects
Ans. 
=== is strict equality operator, while == is loose equality operator. === is commonly used in real-time projects for accurate comparisons.
• === is a strict equality operator that checks both value and type of operands

• == is a loose equality operator that only checks the value of operands

• === is commonly used in real-time projects to ensure accurate comparisons and prevent unexpected type coercion issues
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Q5. Write arrow function syntax
Ans. 
Arrow function syntax in JavaScript
• Arrow functions are concise syntax for writing function expressions in JavaScript

• They have a shorter syntax compared to traditional function expressions

• They do not have their own 'this', 'arguments', 'super', or 'new.target' keywords
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Q6. What is difference between arrow function and anonymous function
Ans. 
Arrow functions are concise syntax for writing function expressions, while anonymous functions do not have a name.
• Arrow functions have a shorter syntax compared to anonymous functions.

• Arrow functions do not have their own 'this' keyword, while anonymous functions do.

• Arrow functions do not have 'arguments' object, while anonymous functions do.

• Arrow functions are not hoisted, while anonymous functions are hoisted.
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It was online 60min test.

It was offline 30 min test.

Q1. Oops,dbms,css,html,dsa,java.
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Q2. It was very friendly .
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Q1. What are the 4 principles of oops?
Ans. 
The 4 principles of OOP are Inheritance, Encapsulation, Abstraction, and Polymorphism.
• Inheritance allows a class to inherit properties and behavior from another class.

• Encapsulation restricts access to certain components within a class, protecting the data.

• Abstraction hides complex implementation details and only shows the necessary features.

• Polymorphism allows objects to be treated as instances of their parent class.
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Q2. What is the difference between string buffer and string builder?
Ans. 
String buffer is synchronized and thread-safe, while string builder is not synchronized and faster.
• String buffer is synchronized, making it thread-safe for use in multi-threaded environments.

• String builder is not synchronized, providing better performance in single-threaded applications.

• String builder is faster than string buffer due to lack of synchronization overhead.

• Example: StringBuffer sb = new StringBuffer(); Str
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Q3. Why strings are immutable?
Ans. 
Strings are immutable in order to ensure data integrity and security.
• Immutable strings prevent accidental data modification, ensuring data integrity.

• Immutable strings enhance security by preventing unauthorized access or tampering.

• Immutable strings allow for more efficient memory management and optimization.

• Example: 'Hello' cannot be changed to 'Hella' directly, a new string must be created.
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Q4. What are the different types of exception in java?
Ans. 
There are two types of exceptions in Java: checked exceptions and unchecked exceptions.
• Checked exceptions are checked at compile time and must be handled using try-catch or throws keyword.

• Unchecked exceptions are not checked at compile time and include RuntimeException and its subclasses.

• Examples of checked exceptions include IOException, SQLException, and ClassNotFoundException.

• Examples of unchecked exceptions include...read more
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Q5. Explain linear search algorithm.
Ans. 
Linear search is a simple searching algorithm that sequentially checks each element in a list until a match is found.
• Iterate through each element in the list

• Compare the current element with the target value

• Return the index if a match is found, otherwise return -1
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Q6. Difference between JDK jvm and jre
Ans. 
JDK includes JRE and development tools, while JRE includes only the Java Runtime Environment.
• JDK stands for Java Development Kit, which includes JRE and development tools like compilers and debuggers.

• JRE stands for Java Runtime Environment, which includes JVM and libraries necessary to run Java applications.

• JVM stands for Java Virtual Machine, which is responsible for executing Java bytecode.

• JDK is used for developing ...read more
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It was online 1hr test. Overall it was an easy test. If you code on hackerrank, hackerearth or leetcode then you can easily clear the test.

Q1. All Data Structure related, OOPs concepts, Spring Framework.
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Q1. Where do you see yourself in 5 years?
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Q2. Why should we hire you?
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