JavaScript Questions (Beginner → Advanced)

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① Beginner Level – Functions & Logic
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① Write a function to calculate the total price of items in a shopping cart.
② Create a function that validates user input such as email or phone number.
③ Write a function to check whether a password is strong.
④ Create a function that converts a date into a readable format.
⑤ Write a function to calculate age from a given birth year.

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② Beginner–Intermediate – Arrays & Array Methods
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① Filter active users from an array of user objects.
② Calculate the total salary of employees using reduce().
③ Sort a list of products by price from low to high.
④ Remove duplicate values from an array.
⑤ Group students by grade using array methods.

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③ Intermediate – Objects & Classes
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① Create a User class with login and logout methods.
② Design a BankAccount class with deposit and withdraw functionality.
③ Create a Product class and calculate discounted prices.
④ Explain how JavaScript objects represent real-world entities.
⑤ Create multiple instances from a class and manage their data.

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④ Intermediate – Inheritance & OOP
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① Create an Employee class and extend it into Manager and Developer classes.
② Override a method in a child class and explain why it is useful.
③ Explain the use of the super keyword with a real-world example.
④ Design a vehicle system using inheritance.
⑤ Explain encapsulation with a real-world scenario.

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⑤ Advanced – Asynchronous JavaScript
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① Simulate an API call using Promise and setTimeout.
② Fetch user data asynchronously and handle errors properly.
③ Explain async and await using a real-world use case.
④ Create a retry mechanism for a failed asynchronous operation.
⑤ Explain how JavaScript handles multiple async tasks at the same time.

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⑥ Advanced – Real-World Scenarios
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① Design an order management system using classes.
② Create a task scheduling system using asynchronous operations.
③ Build the logic for a notification system without UI.
④ Design a role-based access control system.
⑤ Explain how you would structure a JavaScript project for backend use.