type-fest/.github/contributing.md

Contributing guidelines

Submitting a new type

• One type addition per pull request, unless they are connected.
• Please help review the other open pull requests.
  • If there are no open pull requests, provide some feedback on some of the open issues.
• Example of a type contribution.
• Create a new file in the test-d directory and write at least one type test.
  • See the other tests for inspiration.
  • If it makes sense, also write a negative test using expectNotAssignable() or, to test other diagnostics, expectError().
• Don't use one-character type names like T and U. Use descriptive names. See the existing types for inspiration.
• Follow the existing code style, even in documentation code examples.
  • Don't prefix each line in documentation comments with *.
• Write a good documentation comment that includes:
  • Write a short and clear description of what the type does.
    • The first line should match the description in the readme.
  • Write about some real-world use-cases where it can be useful. (It can be hard sometimes for users to see where they would use something)
  • Example code block with a realistic example.
  • At the bottom, explain how the type works. Some types can be quite advanced and hard to understand. We can use this opportunity to teach users.
  • If there has been any discussion somewhere about this type, include a link to it. For example, a discussion on the TypeScript issue tracker.
  • Add relevant @category tags. See other types for examples.
• If you add any internal helper types, they should still be properly documented and tested.
• Add the type to the readme.
• Make sure the file in the source directory uses a .d.ts extension and not .ts.
• Use AI (like ChatGPT) to catch type bugs, improve docs, spot typos, validate examples, and suggest more tests. Include all relevant code (type, tests, helpers, etc.) in the prompt, and also provide a couple of existing types as examples of how it's done. Try this prompt: “Review this TypeScript type for correctness, edge cases, naming, docs, and test coverage. Suggest improvements and realistic succint examples.”
• Run $ npm test before submitting and make sure it passes.
• Name the pull request Add `TypeName` type.