deno/.github/CONTRIBUTING.md

Contributing To Deno

Check the roadmap before contributing.

Please don't make the benchmarks worse.

Ask for help in the issues or on the chat room.

Progress towards future releases is tracked here.

Docs are here.

Submitting a pull request

Before submitting, please make sure the following is done:

1. Ensure ./tools/test.py passes.
2. Format your code with ./tools/format.py.
3. Make sure ./tools/lint.py passes.

Changes to third_party

Changes to third_party including any changes in the package.json will impact the denoland/deno_third_party repository as well.

Adding Ops (aka bindings)

We are very concerned about making mistakes when adding new APIs. When adding an Op to Deno, the counterpart interfaces on other platforms should be researched. Please list how this functionality is done in Go, Node, Rust, and Python.

As an example, see how deno.rename() was proposed and added in PR #671.

Documenting APIs

It is important to document public APIs and we want to do that inline with the code. This helps ensure that code and documentation are tightly coupled together.

Utilize JSDoc

All publicly exposed APIs and types, both via the deno module as well as the global/window namespace should have JSDoc documentation. This documentation is parsed and available to the TypeScript compiler, and therefore easy to provide further downstream. JSDoc blocks come just prior to the statement they apply to and are denoted by a leading /** before terminating with a */. For example:

/** A simple JSDoc comment */
export const FOO = "foo";

JSDoc style guide

• It is important that documentation is easily human readable, but there is also a need to provide additional styling information to ensure generated documentation is more rich text. Therefore JSDoc should generally follow markdown markup to enrich the text.
• While markdown supports HTML tags, it is forbidden in JSDoc blocks.
• Code string literals should be braced with the back-tick (`) instead of quotes. For example:

  /** Import something from the `deno` module. */
  

• Do not document function arguments unless they are non-obvious of their intent (though if they are non-obvious intent, the API should be considered anyways). Therefore @param should generally not be used.
• Vertical spacing should be minimized whenever possible. Therefore single line comments should be written as:

  /** This is a good single line JSDoc */
  

  And not:

  /**
   * This is a bad single line JSDoc
   */
  

• Code examples should not utilise the triple-back tick (```) notation or tags. They should just be marked by indentation, which requires a break before the block and 6 additional spaces for each line of the example. This is 4 more than the first column of the comment. For example:

  /** A straight forward comment and an example:
   *
   *       import { foo } from "deno";
   *       foo("bar");
   */
  

• Code examples should not contain additional comments. It is already inside a comment. If it needs further comments is not a good example.