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Interfaces & Type Aliases

Interfaces

Defining Object Shapes
💡 Interface, EK, "CONTRACT" hai — YE, DEFINE, karta hai, ki, EK, OBJECT, mein, KAUN, se, PROPERTIES, hone, CHAHIYE, aur, UNKE, TYPES, KYA, HONE, CHAHIYE — JAISE, EK, JOB, CONTRACT, mein, RESPONSIBILITIES, LIST, hoti, HAIN.

interface, keyword, se, EK, OBJECT, ki, SHAPE, DEFINE, ki, ja, sakti hai — PROPERTY, naam, aur, TYPES, SPECIFY, kiye, jaate, HAIN. KOI, BHI, OBJECT, JO, US, SHAPE, ko, MATCH, karta hai, WOH, INTERFACE, ko, "IMPLEMENT" karta, hai (EXPLICITLY, DECLARE, kiye, BINA).

TypeScript, "structural, typing" USE, karta hai — AGAR, EK, OBJECT, ki, SHAPE, INTERFACE, ko, MATCH, karti, hai, WOH, VALID, hai, CHAHE, WOH, OBJECT, EXPLICITLY, "implements" KEYWORD, ke, saath, DECLARE, na, kiya, gaya, ho.

interface User {
  name: string;
  age: number;
  email: string;
}

function greetUser(user: User) {
  console.log(`Hello, ${user.name}`);
}

greetUser({ name: "Aarav", age: 22, email: "aarav@example.com" });   // OK
greetUser({ name: "Priya", age: 25 });   // ERROR — email missing
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Interface, EK, "CONTRACT" hai — YE, DEFINE, karta hai, ki, EK, OBJECT, mein, KAUN, se, PROPERTIES, hone, CHAHIYE, aur, UNKE, TYPES, KYA, HONE, CHAHIYE — JAISE, EK, JOB, CONTRACT, mein, RESPONSIBILITIES, LIST, hoti, HAIN.
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⚡ Quick Recap
  • interface = object ki, SHAPE, define, karta, hai (properties + types)
  • TypeScript, structural, typing, use, karta, hai — shape, matter, karta, hai, naam, nahi
  • Function parameters, ke, TYPE, ki, tarah, interfaces, EXTREMELY, COMMON, hain
On this page (2 subtopics)

Index, signatures, se, EK, interface, DEFINE, ki, ja, sakti, hai, JISME, PROPERTY, NAMES, PEHLE, se, PATA, NAHI, HAIN — jaise, interface Dictionary { [key: string]: number }, KISI, BHI, string, KEY, ke, saath, USE, ho, sakta hai.

interface Dictionary {
  [key: string]: number;
}
const scores: Dictionary = { math: 90, science: 85 };

Interfaces, mein, FUNCTION, TYPES, bhi, DEFINE, kiye, ja, sakte, hain — jaise, EK, "callable" interface, JO, EK, function, ki, tarah, INVOKE, ki, ja, sakti, hai.

💡Tip: Interfaces, mein, FUNCTIONS, DEFINE, karne, ke, DO, WAYS, hain — method, syntax, (greet(): void) YA, property, syntax, (greet: () => void) — DONO, ka, BEHAVIOR, SLIGHTLY, DIFFERENT, hai.