TypeScript is a statically-typed superset of JavaScript that adds optional type annotations to the language. It provides developers with the ability to catch errors early during the development process and enhances code maintainability and scalability. TypeScript compiles down to plain JavaScript and is supported by popular code editors and frameworks. With its type system, TypeScript offers features like type inference, interfaces, classes, and modules, allowing developers to write more robust and predictable code. It seamlessly integrates with existing JavaScript projects and enables gradual adoption, as JavaScript code is valid TypeScript code. TypeScript has gained significant popularity among developers, especially for building large-scale applications, as it offers the advantages of static typing without sacrificing the flexibility and expressiveness of JavaScript.