WITS Innovation Lab Node JS Developer Interview Questions and Answers

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.

Very easy roundand is it a program to implement Parallel Merge Sort and can measure the performance

Coding and decoding reasoning for the shield season is over now I am not sure

Q1. What are oops concepts in java, explain real time scenario
Ans. 
OOPs concepts in Java include inheritance, polymorphism, encapsulation, and abstraction.
• Inheritance allows a subclass to inherit properties and methods from a superclass.

• Polymorphism allows objects to take on multiple forms and behave differently based on their context.

• Encapsulation hides the implementation details of an object and only exposes necessary information.

• Abstraction allows for the creation of abstract class...read more
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Q2. Uses of interface, inheritance
Ans. 
Interfaces define contracts for behavior, while inheritance allows for code reuse and polymorphism.
• Interfaces allow for loose coupling and abstraction, enabling multiple implementations of the same behavior.

• Inheritance allows for code reuse and extension of existing classes, reducing code duplication.

• Polymorphism allows objects of different classes to be treated as if they were of the same class, simplifying code and i
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Q3. SQL query for join of tables
Ans. 
SQL query for joining tables
• Use JOIN keyword to combine two or more tables based on a related column

• Specify the columns to be selected using SELECT keyword

• Use ON keyword to specify the condition for joining the tables

• Different types of joins include INNER JOIN, LEFT JOIN, RIGHT JOIN, and FULL OUTER JOIN
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Q4. Java concepts used in your project
Ans. 
Used Java concepts such as inheritance, polymorphism, and exception handling in my project.
• Implemented inheritance to create a base class and derived classes with specific functionalities.

• Utilized polymorphism to allow objects of different classes to be treated as if they were of the same class.

• Implemented exception handling to handle errors and prevent program crashes.

• Used interfaces to define a set of methods that a ...read more
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Q5. Overloading vs overriding, practical uses
Ans. 
Overloading is having multiple methods with the same name but different parameters. Overriding is having a method in a subclass with the same name and parameters as a method in the superclass.
• Overloading is used to provide different ways to call a method with different parameters

• Overriding is used to provide a specific implementation of a method in a subclass

• Overloading is resolved at compile-time while overriding is r...read more
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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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