A Tuple in TypeScript is a special type of array where:

• Order matters
• Fixed number of elements
• Each position can have a different data type

---

Basic Syntax

let user: [string, number];

user = ["Raj", 25];

Here:

• First value → string
• Second value → number

---

Why Tuple?

Normal arrays allow any order:

let arr: (string | number)[] = [25, "Raj"];

But tuple keeps strict order:

let user: [string, number];

user = ["Raj", 25]; // ✅
user = [25, "Raj"]; // ❌ Error

---

Real-world Example

User Information

let employee: [number, string, boolean];

employee = [101, "Amit", true];

Meaning:

• ID → number
• Name → string
• Active status → boolean

---

Accessing Tuple Values

let student: [string, number] = ["Rahul", 90];

console.log(student[0]); // Rahul
console.log(student[1]); // 90

---

Tuple with Optional Values

let user: [string, number?];

user = ["Raj"];
user = ["Raj", 25];

? means optional.

---

Readonly Tuple

let color: readonly [string, string] = ["red", "blue"];

// color[0] = "green"; ❌ Error

---

Tuple with Destructuring

let person: [string, number] = ["Raj", 25];

let [name, age] = person;

console.log(name);
console.log(age);

---

Tuple in Function Return

Very common in real projects.

function getUser(): [string, number] {
    return ["Raj", 25];
}

const [name, age] = getUser();

---

Difference Between Array and Tuple

Feature	Array	Tuple
Size	Dynamic	Fixed
Order	Not important	Important
Types	Same or mixed	Fixed per position
Example	string[]	[string, number]

---

Interview Definition

A Tuple in TypeScript is a fixed-size typed array where each element can have a different data type and specific position.