TypeScript, developed and maintained by Microsoft, extends JavaScript by adding static type definitions, interfaces, and advanced tooling support. It allows developers to catch errors early through type checking, improves IDE autocompletion, and enables more robust refactoring in complex codebases. As the preferred language for many modern frameworks like Angular and default scaffolds in React, Vue, and Next.js, TypeScript has become the foundation of enterprise-scale and AI-assisted coding. In 2025, it overtook Python and JavaScript as the most used language on GitHub, marking a significant milestone in developer evolution.