The Billion Dollar Mistake
JavaScript is famously loose. You can pass a string to a function expecting a number, and JS will just try to guess what you meant. This leads to the infamous 'cannot read property of undefined' crash in production apps, costing companies millions.
Enter TypeScript
TypeScript is just JavaScript with strict type checking. It catches your errors in the code editor (VS Code) *before* you even run the app. It acts as self-documenting code. If you define a `User` interface, the editor will auto-complete `user.email` and yell at you if you type `user.emal`.
The Industry Standard
In 2026, writing enterprise applications in plain JavaScript is considered malpractice. Every major library (React, Next.js, Prisma) is built with TypeScript first.