TypeScript Ka Taaruf

TypeScript, JavaScript ka ek superset hai — har valid JavaScript program pehle se hi valid TypeScript hota hai. TypeScript jo upar se add karta hai woh ek type system hai: aap apne data ka shape describe kar sakte hain (strings, numbers, objects, functions), aur compiler check karta hai ke aapka code un shapes ko asal mein respect karta hai, iss se pehle ke woh chale.

TypeScript code directly nahi chalta — yeh pehle plain JavaScript mein compile hota hai. Type annotations sirf isliye hote hain taake code likhte waqt mistakes pakri ja sakein; ek baar compile hone ke baad, output ek normal JavaScript hota hai jisme type information hata di gayi hoti hai, aur wahi asal mein execute hota hai.

Types ki zaroorat kyun hai?

Code chalane se pehle hi bugs pakarna — property name mein typo, ya ghalat kism ki value pass karna, foran ek error ke tor par nazar aa jaata hai, runtime surprise ke bajaye
Behtar editor support — autocomplete, inline documentation, aur mehfooz renaming, sab is baat par inhisar karte hain ke editor ko pata ho ke ek value kis type ki hai
Khud ba khud documented code — ek function ki type signature aapko batati hai ke woh kya expect karta hai aur kya wapas karta hai, uski implementation parhe baghair
Zyada mehfooz refactoring — ek type ka shape badalte hi, woh har jagah flag ho jaati hai jahan purane shape ko farz kiya gaya tha

Ek jaldi si jhalak

Yeh raha real TypeScript ka ek program, jo is page ke apne compiler par waqai chala hai — koi mockup nahi:

main.ts

Khud try karo →

let greeting: string = "Hello from TypeScript!";
console.log(greeting);

Output

Hello from TypeScript!

Bas itna hi — ek normal variable, bas ek explicit type ke sath. Agla lesson aapka pehla poora program chalata hai aur theek se samjhaata hai ke kya ho raha hai.

Aapka Pehla TypeScript Program →