TypeScript Props Extraction

TypeScript props extraction pulls component prop definitions from TypeScript source code to generate documentation automatically. This technique leverages the type information already present in well-typed components. Extraction tools parse interface definitions and type annotations to produce structured documentation data.

What Is TypeScript Props Extraction

TypeScript props extraction refers to the process of analyzing TypeScript component files to identify and document component props. Extraction tools read interface definitions, type aliases, and inline type annotations to determine what props a component accepts, their types, optional status, and default values.

This extraction enables automatic documentation generation that stays synchronized with code. When developers modify prop types, documentation tools detect these changes and update documentation accordingly. The approach eliminates manual documentation of technical details that TypeScript already defines.

How TypeScript Props Extraction Works

Extraction tools parse TypeScript files using the TypeScript compiler API or similar parsing libraries. The parser builds an abstract syntax tree representing the code structure. Analysis identifies component definitions and their associated prop types, whether defined as interfaces, type aliases, or inline types.

The tool resolves type references to understand complex types. A prop typed as ButtonVariant requires following that reference to understand the actual values. Generic types require additional handling to document type parameters meaningfully. Intersection and union types combine information from multiple sources.

JSDoc comments adjacent to prop definitions or interface properties provide description text. Extraction tools associate these comments with their corresponding props. The output is structured data, typically JSON, containing prop names, types, descriptions, defaults, and required status.

Key Considerations

• Interface definitions provide clearer extraction than inline types due to explicit structure
• JSDoc comments on interface properties become prop descriptions in generated documentation
• Generic components require special handling to document type parameters meaningfully
• Default values in destructuring patterns can be extracted to show prop defaults

Common Questions

Which tools support TypeScript props extraction for documentation?

Several tools support TypeScript props extraction with varying capabilities. React-docgen-typescript analyzes React components specifically, handling TypeScript interfaces and types well. Storybook uses react-docgen-typescript or its own extraction for autodocs. TypeDoc generates documentation for any TypeScript code, including components. API Extractor from Microsoft extracts and documents public APIs. Teams should evaluate tools based on framework compatibility, output format needs, and integration with their documentation setup.

How do teams handle props inherited from extended interfaces?

Inherited props from extended interfaces require careful handling in extraction. Some tools flatten inheritance, showing all props regardless of source. Others group props by source interface, helping users understand prop origins. Documentation should indicate which props come from base interfaces like HTMLAttributes versus component-specific props. Teams can use type utilities like Omit to exclude irrelevant inherited props from documentation. Clear documentation structure helps users navigate components that extend complex base types.

Summary

TypeScript props extraction enables automatic documentation generation from existing type definitions. This approach maintains documentation accuracy with minimal manual effort. Teams benefit from combining TypeScript’s type safety with documentation generation to produce comprehensive, reliable component API references.