Tuple with fixed length and types in Typescript

Introduction

A tuple lets you store a fixed number of values, each with a specific type. It helps keep data organized and safe.

When you want to group a few related values of different types together, like a person's name and age.

When you need to return multiple values from a function with known types and order.

When you want to represent a fixed structure, like a coordinate with x and y numbers.

When you want to ensure the data always has the same length and types in the same order.

Syntax

Typescript

let variableName: [type1, type2, type3];

// Example:
let person: [string, number];

Each position in the tuple has a fixed type.

The length of the tuple is fixed by the number of types you list.

Examples

A tuple with two numbers representing a point's x and y coordinates.

Typescript

let point: [number, number];
point = [10, 20];

A tuple with a string, number, and boolean for a user's name, age, and active status.

Typescript

let user: [string, number, boolean];
user = ['Alice', 30, true];

A tuple with zero elements, always empty.

Typescript

let emptyTuple: [];
emptyTuple = [];

Sample Program

This program defines a function that returns a tuple with a name and age. It then prints them.

Typescript

function getUserInfo(): [string, number] {
  return ['Bob', 25];
}

const userInfo: [string, number] = getUserInfo();
console.log(`Name: ${userInfo[0]}, Age: ${userInfo[1]}`);

Important Notes

You cannot add or remove elements from a tuple; its length is fixed.

Access tuple elements by their position, starting at 0.

TypeScript will check the types and order to prevent mistakes.

Summary

Tuples store a fixed number of values with specific types.

They help keep related data organized and type-safe.

Use tuples when you know the exact number and types of elements.