TypeScript Basic Types


TypeScript: Basic Types

  • TypeScript helps you clearly define what kind of data you're working with.
  • In regular JavaScript, variables can be anything — a number, a string, an object... and that can lead to confusing bugs.
  • With TypeScript, you can declare the kind of value a variable should hold. This makes your code more reliable.

Common Types in TypeScript

Here’s a quick guide to some basic data types:

1. number

Used for all numeric values — whole numbers, decimals, etc.

let age: number = 25; 

2. string

Used for text — anything inside quotes.

let name: string = "Sahand";

3. boolean

Represents true or false values.

let isActive: boolean = true;

4. array

Used to store a list of values of the same type.

let scores: number[] = [90, 85, 100];

5. any

Can be any type — useful when you’re not sure what kind of value you’ll get.

let something: any = "Hello"; 
Something = 42; // also valid 
Avoid using any too much — it defeats the purpose of type checking!

6. object

Used for structured data with key-value pairs.

let user: { name: string; age: number } = {   
      name: "Sahand",   
      age: 30, 
}; 

7. tuple

An array with a set number of items, where each spot can hold a different kind of value.

let userInfo: [string, number] = ["Sahand", 30];

8. enum

A way to give names to sets of values.

enum Direction {   
    Up,   
    Down,   
    Left,   
    Right, 
} 
 Let move: Direction = Direction.Left; 

9. undefined & null

Used to represent empty or unknown values.

let data: undefined = undefined;
Let nothing: null = null; 

Why Use Types?

Using these types lets TypeScript help you write clean, bug-free code by warning you when something doesn’t match the expected data format.


Prefer Learning by Watching?

Watch these YouTube tutorials to understand TYPESCRIPT Tutorial visually:

What You'll Learn:
  • 📌 TypeScript tutorial for beginners #5 Types | number | string etc
  • 📌 TypeScript #3 - Basic Types
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