Today! We’re going to Continue TypeScript learning like you’re a smart 5-year-old who loves to build things and asks “why?” (which is the best thing ever).

& yes “why?” is my way of learning.

I've divided this into 20 Chapters. and will go one by one and each will be of 2 - 3 min. of read.
This is a Continuation, if you have not read Previous chapter - Chapter 3

This is Chapter ⓸ TS Mastering

🧩 Chapter 5: Type Aliases & Interfaces

(aka: “Why repeat yourself when you can name your thing once?”)

🎭 Imagine this:

You keep writing this:

let person: { name: string; age: number; isCool: boolean }

over and over and over again... 🥱

Wouldn’t it be cool to say:

“Let’s call a common type for Person!”

✅ Type Aliases – Give a shape a nickname

Think of it like, using a same type instance for similar type of objects.
Here Both, me and friend is of type - Person

type Person = {
  name: string;
  age: number;
  isCool: boolean;
};

let me: Person = {
  name: "Karandeep Singh",
  age: 25,
  isCool: true,
};
let friend: Person = {
  name: "some name",
  age: 25,
  isCool: true,
};

Now, instead of rewriting the full type again & again, just say :Person as the type for every person object you create.

🤝 Interfaces – Like type, but for teamwork!

interface Car {
  brand: string;
  speed: number;
  electric?: boolean; // optional
}

let myCar: Car = {
  brand: "BMW M5",
  speed: 200,
};

Interfaces are great when many people or pieces of code work together, like a contract everyone agrees on 🤝

🥊 Type vs Interface: What’s the difference?

For most cases, either works fine — go with what feels good!

🔧 Extending Types – Inheritance!

type Animal = {
  name: string;
};

type Dog = Animal & {
  barkVolume: number;
};

let d: Dog = {
  name: "Bruno",
  barkVolume: 8,
};

OR using interface:

interface Animal {
  name: string;
}

interface Dog extends Animal {
  barkVolume: number;
}

Both ways say:

"Dog is like Animal… plus extra properties"

If you enjoyed this and want to master TypeScript and other technologies, follow the series and drop a like!🤝

I’m a passionate software developer sharing the cool things I discover, hoping they help you level up on your coding journey.

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