What is TypeScript?

TypeScript is a strongly typed programming language that builds on JavaScript, developed and maintained by Microsoft. Released in 2012, TypeScript adds optional static type definitions to JavaScript, enabling better tooling, error detection, and code quality.

TypeScript compiles to plain JavaScript, meaning it runs anywhere JavaScript runs. All valid JavaScript code is also valid TypeScript, making migration and adoption straightforward.

Industry Adoption: TypeScript is used by Google (Angular), Microsoft (VS Code), Airbnb, Slack, and thousands of other companies for large-scale JavaScript applications.

Key Features

  • Static Typing: Catch errors at compile time
  • Type Inference: Smart type detection
  • Interfaces: Define object shapes
  • Generics: Write reusable, type-safe code
  • Modern JavaScript: ES6+ features supported
  • Enums: Strongly-typed named constants
  • Decorators: Metaprogramming support
  • Excellent Tooling: IntelliSense, refactoring, navigation

Common Uses

  • Large-scale web applications
  • Angular framework development
  • React and Vue.js with type safety
  • Node.js backend services
  • VS Code extensions
  • React Native mobile apps
  • Electron desktop applications
  • APIs and microservices

Advantages

  • Catches bugs early during development
  • Superior code editor support (IntelliSense)
  • Easier refactoring and maintenance
  • Excellent for large codebases
  • Compiles to JavaScript (universal compatibility)
  • Growing ecosystem and community
  • Better documentation through types
  • Gradual adoption possible

Limitations

  • Compilation step required
  • Learning curve for JavaScript developers
  • Additional build tooling complexity
  • Type definitions needed for third-party libraries
  • Can be verbose for simple projects
  • Not true static typing (runtime is still JavaScript)

Technical Information

File extension .ts, .tsx (React), .d.ts (type definitions)
MIME type text/x-typescript, application/x-typescript
Developer Microsoft (Anders Hejlsberg lead)
First Release October 1, 2012
Current Version TypeScript 5.3+ (2024)
Typing Static, optional, structural
Paradigm Multi-paradigm: object-oriented, functional, imperative
License Apache License 2.0