Problem 1:

Description: Create a function that takes a string and an optional boolean.

• If the boolean is true or not provided, return the string in uppercase.
• If the boolean is false, return the string in lowercase.

Function Signature:

function formatString(input: string, toUpper?: boolean): string

Example:

formatString("Hello");          // Output: "HELLO"
formatString("Hello", true);   // Output: "HELLO"
formatString("Hello", false);  // Output: "hello"

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Problem 2:

Description: Create a function that filters an array of objects by the rating property, returning only items with a rating of 4 or more.

Function Signature:

function filterByRating(items: { title: string; rating: number }[]): { title: string; rating: number }[]

Example:

const books = [
  { title: "Book A", rating: 4.5 },
  { title: "Book B", rating: 3.2 },
  { title: "Book C", rating: 5.0 }
];

filterByRating(books); 
// Output: [ { title: "Book A", rating: 4.5 }, { title: "Book C", rating: 5.0 } ]

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Problem 3:

Description: Create a generic function that concatenates multiple arrays of the same type using rest parameters.

Function Signature:

function concatenateArrays<T>(...arrays: T[][]): T[]

Example:

concatenateArrays(["a", "b"], ["c"]);       // Output: ["a", "b", "c"]
concatenateArrays([1, 2], [3, 4], [5]);     // Output: [1, 2, 3, 4, 5]

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Problem 4:

Description:

• Create a Vehicle class with private make and year properties and a getInfo() method.
• Create a Car class extending Vehicle, adding a private model property and a getModel() method.

Example:

const myCar = new Car("Toyota", 2020, "Corolla");
myCar.getInfo();   // Output: "Make: Toyota, Year: 2020"
myCar.getModel();  // Output: "Model: Corolla"

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Problem 5:

Description: Write a function that takes a string | number and returns:

• The length if it's a string
• The number multiplied by 2 if it's a number

Function Signature:

function processValue(value: string | number): number

Example:

processValue("hello"); // Output: 5
processValue(10);      // Output: 20

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Problem 6:

Description: Define an interface Product and create a function to find the product with the highest price in an array. If the array is empty, return null.

Interface & Function Signature:

interface Product {
  name: string;
  price: number;
}

function getMostExpensiveProduct(products: Product[]): Product | null

Example:

const products = [
  { name: "Pen", price: 10 },
  { name: "Notebook", price: 25 },
  { name: "Bag", price: 50 }
];

getMostExpensiveProduct(products);  
// Output: { name: "Bag", price: 50 }

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Problem 7:

Description:

• Define an enum Day for the days of the week.
• Create a function that returns "Weekday" or "Weekend" based on the input day.

Enum & Function Signature:

enum Day {
  Monday,
  Tuesday,
  Wednesday,
  Thursday,
  Friday,
  Saturday,
  Sunday
}

function getDayType(day: Day): string

Example:

getDayType(Day.Monday);   // Output: "Weekday"
getDayType(Day.Sunday);   // Output: "Weekend"

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Problem 8:

Description: Create an async function that:

• Returns the square of a number after 1 second
• Rejects if the number is negative

Function Signature:

async function squareAsync(n: number): Promise<number>

Example:

squareAsync(4).then(console.log);        // Output after 1s: 16
squareAsync(-3).catch(console.error);    // Output: Error: Negative number not allowed

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🎯 Interview Questions - Blog Task

Write an impactful blog post on 2 of the following questions:

1. What are some differences between interfaces and types in TypeScript?
2. What is the use of the keyof keyword in TypeScript? Provide an example.
3. Explain the difference between any, unknown, and never types in TypeScript.
4. What is the use of enums in TypeScript? Provide an example of a numeric and string enum.
5. What is type inference in TypeScript? Why is it helpful?
6. How does TypeScript help in improving code quality and project maintainability?
7. Provide an example of using union and intersection types in TypeScript.

✅ Instructions:

• Choose any 2 topics from the list and write a blog post about them.

• Present your blog through the README.md file in your GitHub repository.

• All solutions must be in a single TypeScript file.

• Do not include comments like “Problem 1”, “Problem 2”, etc., in your code.

• Use meaningful names for all variables, functions, and classes.

• Ensure the code is original.

  ⚠️ Plagiarism (copying from friends or online sources) will result in a zero.

• Submit a GitHub public repository link containing your:

  • Solutions file
  • README.md with the blog content

📤 Submission Guidelines:

• 🔗 Submit: GitHub Public Repository Link
• 📝 Ensure: The blog content is inside the README.md file
• 📂 Organize: All code and documentation should be in one repo

🕒 Assignment Deadlines:

• 60 Marks: May 08, 2025 – before 11:59 PM
• 50 Marks: May 09, 2025 – before 11:59 PM
• 30 Marks: After May 09, 2025

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