TypeScript: tipizatsiya dlya JavaScript proektov

TypeScript — tipizirovannyy nadmnozhestvo JavaScript, kompiliruemoe v JS. Dobavlyaet staticheskuyu tipizatsiyu i sovremennye vozmozhnosti.

Preimuschestva TypeScript

• Obnaruzhenie oshibok na etape kompilyatsii
• Avtodopolnenie v IDE
• Refaktoring s uverennostyu
• Dokumentatsiya cherez tipy

Bazovye tipy

// Primitivylet name: string = "John";let age: number = 30;let isActive: boolean = true;

// Massivylet numbers: number[] = [1, 2, 3];let names: Array<string> = ["John", "Jane"];

// Obektyinterface User {  id: number;  name: string;  email?: string; // optsionalnoe}

const user: User = { id: 1, name: "John" };

Generics

function identity<T>(arg: T): T {  return arg;}

// Ispolzovanielet output = identity<string>("myString");let outputNum = identity(123); // tip vyvoditsya avtomaticheski

Migratsiya s JavaScript

1. Dobavte tsconfig.json
2. Pereimenuyte fayly .js → .ts
3. Ustanovite allowJs: true
4. Postepenno dobavlyayte tipy

React + TypeScript

interface Props {  title: string;  count?: number;}

const Component: React.FC<Props> = ({ title, count = 0 }) => {  return <div>{title}: {count}</div>;};