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Learn/TypeScript/TypeScript Core
TypeScript•TypeScript Core

TypeScript Simple Types

TypeScript enhances JavaScript by adding static types.

JavaScript and TypeScript Primitives

The most basic types in TypeScript are called primitives. These types form the building blocks of more complex types in your applications. TypeScript includes all JavaScript primitives plus additional type features. Here are the five primitive types you'll use most often:

Boolean

Formula

Represents true/false values.

Used for flags, toggles, and conditions.

Example

let isActive: boolean = true;
let hasPermission = false; // TypeScript infers 'boolean' type

Number

Formula

Represents both integers and floating - point numbers.

TypeScript uses the same number type for all numeric values.

Example

let decimal: number = 6;
let hex: number = 0xf00d;       // Hexadecimal let binary: number = 0b1010;     // Binary let octal: number = 0o744;      // Octal let float: number = 3.14;      // Floating point

String

Represents text data. Can use single quotes ('), double quotes ("), or backticks (`) for template literals.

Example

let color: string = "blue";
let fullName: string = 'John Doe';
let age: number = 30;
let sentence: string = `Hello, my name is ${fullName} and I'll be ${age + 1} next year.`;
BigInt (ES2020+)

Represents whole numbers larger than 2

53 - 1.

Example

const hugeNumber = BigInt(9007199254740991);

Symbol

Creates unique identifiers. Useful for creating unique property keys and constants.

Example

const uniqueKey: symbol = Symbol('description');
const obj = {
[uniqueKey]: 'This is a unique property'
};
console.log(obj[uniqueKey]); // "This is a unique property"

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TypeScript Getting Started

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TypeScript Explicit Types and Inference