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Basics

What is TypeScript?

JavaScript with Types
💡 TypeScript, EK, "SPELL-CHECKER" hai, CODE, ke, liye — JAISE, EK, SPELL-CHECKER, TYPING, karte, waqt, hi, MISTAKES, PAKADТА, hai (PAGE, PRINT, hone, se, PEHLE), TypeScript, TYPE, MISMATCHES, ko, CODE, RUN, hone, se, PEHLE, hi, PAKADТА, hai.

TypeScript, Microsoft, dwara, BANAYA, gaya, EK, OPEN-SOURCE, LANGUAGE, hai — JavaScript, ka, EK, SUPERSET, hai, ISKA, MATLAB, HAR, VALID, JavaScript, CODE, VALID, TypeScript, bhi, hai. TypeScript, ISME, STATIC, TYPES, ADD, karta hai.

TypeScript, CODE, ko, BROWSER, DIRECTLY, RUN, NAHI, kar, sakta — TypeScript, COMPILER, (tsc) ISE, PLAIN, JavaScript, mein, TRANSPILE, karta hai, JO, PHIR, KISI, BHI, JavaScript, ENVIRONMENT, mein, RUN, ho, sakta hai.

// TypeScript code:
function greet(name: string): string {
  return "Hello, " + name;
}

greet(42);   // COMPILE-TIME error — number, string, ki, jagah, nahi, ja, sakta

// Compiled JavaScript (types, REMOVE, ho, jaate, hain):
function greet(name) {
  return "Hello, " + name;
}
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TypeScript, EK, "SPELL-CHECKER" hai, CODE, ke, liye — JAISE, EK, SPELL-CHECKER, TYPING, karte, waqt, hi, MISTAKES, PAKADТА, hai (PAGE, PRINT, hone, se, PEHLE), TypeScript, TYPE, MISMATCHES, ko, CODE, RUN, hone, se, PEHLE, hi, PAKADТА, hai.
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⚡ Quick Recap
  • TypeScript = JavaScript ka superset, STATIC, TYPES, ke, saath
  • Compiler (tsc), TypeScript, ko, plain, JavaScript, mein, transpile, karta hai
  • Types, sirf, compile-time, PAR, exist, karte, hain — runtime, PAR, erased, ho, jaate, hain
On this page (2 subtopics)

TypeScript, badi, companies, (Microsoft, Google, Airbnb, Slack) mein, WIDELY, ADOPT, ki, gayi, hai — LARGE, codebases, mein, TYPE, SAFETY, se, REFACTORING, aur, MAINTENANCE, KAAFI, EASIER, ho, jaate, HAIN.

💡Tip: 2023, ke, STATE, of, JS, survey, ke, according, TypeScript, MOST, JavaScript, developers, dwara, USE, ki, jaane, waali, TOOL, hai.

TypeScript, errors, DO, categories, mein, AATE, hain — SYNTAX, errors, (INVALID, JavaScript) aur, TYPE, errors, (TYPE, MISMATCH). Type, errors, sirf, COMPILE-TIME, PAR, DIKHТE, HAIN — --noEmitOnError, flag, se, TYPE, errors, hone, PAR, COMPILATION, ROKI, ja, sakti, hai.

// tsc --noEmitOnError, se, type, errors, hone, par, .js, file, generate, NAHI, hoti