TypeScript is an open-source programming language developed by Microsoft that builds upon JavaScript by adding static typing and other features to facilitate the development of large-scale applications. As a strict syntactical superset of JavaScript, TypeScript compiles to plain JavaScript, ensuring compatibility across all browsers and platforms. Key Features and Functionality: - Static Typing: Introduces optional type annotations, enabling compile-time type checking to catch errors early. - Type Inference: Automatically infers types when they are not explicitly defined, reducing the need for repetitive code. - Interfaces and Generics: Supports interfaces for defining contracts within code and generics for creating reusable, type-safe components. - Enumerated Types and Tuples: Provides enumerated types for defining a set of named constants and tuples for handling fixed-size collections of elements. - Namespaces and Modules: Offers namespaces for organizing code and modules for better code encapsulation and reuse. - Compatibility with JavaScript: Allows seamless integration with existing JavaScript codebases and libraries, facilitating gradual adoption. Primary Value and Problem Solved: TypeScript addresses the challenges of developing and maintaining large-scale JavaScript applications by introducing static typing and advanced features that enhance code quality, readability, and maintainability. By catching errors at compile time and providing robust tooling support, TypeScript enables developers to build more reliable and scalable applications. Its compatibility with existing JavaScript code ensures a smooth transition and integration, making it a valuable tool for both new and ongoing projects.