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
Represents true/false values.
Used for flags, toggles, and conditions.
let isActive: boolean = true;
let hasPermission = false; // TypeScript infers 'boolean' type
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Number
Represents both integers and floating-point numbers.
TypeScript uses the same number type for all numeric values.
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
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String
Represents text data.
Can use single quotes ('), double quotes ("), or backticks (`) for template literals.
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.`;
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BigInt (ES2020+)
Represents whole numbers larger than 253 - 1.
Use the n suffix to create a bigint.
const bigNumber: bigint = 9007199254740991n;
const hugeNumber = BigInt(9007199254740991); // Alternative syntax
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Symbol
Creates unique identifiers.
Useful for creating unique property keys and constants.
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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