TypeScript: The Practical Guide for JavaScript Developers (2026) TypeScript isn't just "JavaScript with types" — it's a superpower that catches bugs before they happen. Here's the practical guide to going from JS to TS. Why TypeScript Matters // JavaScript: The bug that only shows in production function calculateDiscount ( price , isMember ) { return price * ( isMember ? 0.9 : 0.8 ); // What if price is "100"? NaN! } // TypeScript: Caught at compile time function calculateDiscount ( price : numb