TypeScript Types for JavaScript Libraries | Generated by AI
Yes, exactly! @types/ packages are TypeScript type definition files for JavaScript libraries.
Here’s how it works:
Many popular JavaScript libraries (like React, Express, Lodash) were written in plain JavaScript before TypeScript existed or without TypeScript in mind. When you use these libraries in a TypeScript project, TypeScript doesn’t know what types the library’s functions expect or return.
The @types/ packages provide these type definitions. For example:
@types/react- type definitions for React@types/node- type definitions for Node.js@types/express- type definitions for Express
These packages are maintained in the DefinitelyTyped repository, a community effort to provide high-quality TypeScript type definitions.
When do you need them?
- If a package is written in JavaScript and doesn’t include its own types
- Modern packages often include their own type definitions (bundled in the package itself), so you don’t need a separate
@types/package
Example:
npm install lodash # JavaScript library
npm install -D @types/lodash # TypeScript definitions
The @types/ package doesn’t change the runtime behavior at all - it just helps TypeScript understand the library’s API during development and compilation.