Mapbox GL JS has API documentation and examples.

Writing API Documentation

API documentation is written as JSDoc comments and processed with documentationjs.

• Classes, methods, events, and anything else in the public interface must be documented with JSDoc comments. Everything outside of the public interface may be documented and must be tagged as @private.
• Text within JSDoc comments may use markdown formatting. Code identifiers must be surrounded by `backticks`.
• Documentation must be written in grammatically correct sentences ending with periods.
• Documentation must specify measurement units when applicable.
• Documentation descriptions must contain more information than what is obvious from the identifier and JSDoc metadata.
• Class descriptions should describe what the class is, or what its instances are. They do not document the constructor, but the class. They should begin with either a complete sentence or a phrase that would complete a sentence beginning with "A T is..." or "The T class is..." Examples: "Lists are ordered indexed dense collections." "A class used for asynchronous computations."
• Function descriptions should begin with a third person singular present tense verb, as if completing a sentence beginning with "This function..." If the primary purpose of the function is to return a value, the description should begin with "Returns..." Examples: "Returns the layer with the specified id." "Sets the map's center point."
• @param, @property, and @returns descriptions should be capitalized and end with a period. They should begin as if completing a sentence beginning with "This is..." or "This..."
• Functions that do not return a value (return undefined), should not have a @returns annotation.
• Member descriptions should document what a member represents or gets and sets. They should also indicate whether the member is read-only.
• Event descriptions should begin with "Fired when..." and so should describe when the event fires. Event entries should clearly document any data passed to the handler, with a link to MDN documentation of native Event objects when applicable.

Writing Examples

Examples are written as Batfish pages in docs/pages/example. Each example requires two files: an .html file containing the source code for the example, and a .js file containing example boilerplate and front matter. The front matter should include the following items:

• title: A short title for the example in sentence case as a verb phrase
• description: A one sentence description of the example
• tags: An array of tags for the example, which determine the sections it is listed in in the sidebar navigation, see docs/data/tags.js for a list of tags
• pathname: The relative path of the example, including leading /mapbox-gl-js/example/ path

In the .html file, write the HTML and JavaScript constituting the example.

• Use 4 space indentation. Exception: do not add an initial level of indentation to code within <script> tags (it should start flush left).
• Do not include an access token in the example code. The access token will be inserted automatically by the template, using the current logged in user's default public token, or a placeholder <insert token here> string if the user is not logged in.
• Do not use custom styles from your personal account. Use only the default mapbox account styles.
• When embedding literal JSON (GeoJSON or Mapbox style snippets) into script code, double-quote property names and string values. Elsewhere, use single-quoted strings.

Every example must have an accompanying image. To get an image, run the site locally and take a screenshot of the rendered map in the example:

1. Run npm run create-image <example-file-name> <mapbox-access-token>. The script will take a screenshot of the map in the example and save it to docs/img/src/. Commit the image.
2. Run npm run start-docs to verify that your example image is loading as expected.

💡 If npm run create-image does not generate an ideal image. You can also take a screenshot of it yourself by running the site locally with npm run start-docs and taking a screenshot of the example map in PNG format. Resize it to 1200 x 500 pixels and save it in the docs/img/src folder.

Running the Documentation Server Locally

To start a documentation server locally run

npm run start-docs

The command will print the URL you can use to view the documentation.

💡 If you receive an error related to @mapbox/appropriate-images, try nvm use 8 && npm run start-docs.

Committing and Publishing Documentation

The mapbox-gl-js repository has both master and publisher-production as active branches. The master branch is used for mainline code development: the next version of mapbox-gl-js will come from the code in this branch, and it may contain documentation and examples for APIs that are not yet part of a public release. The publisher-production branch is published to https://www.mapbox.com/mapbox-gl-js/ on any push to the branch. For the purposes of documentation changes, use these two branches as follows:

• If your changes are relevant to the currently released version, make them on publisher-production. Examples: correcting the API documentation for a released API, adding a new example that depends only on current APIs.
• If your changes depend on gl-js features not in the currently released version, make them on master. Examples: documenting or adding an example for a newly-added API.

When releasing, the release manager will:

• Merge publisher-production to master, ensuring that any accumulated changes in publisher-production propagate to master
• Make the release
• Fast-forward publisher-production to the current master, ensuring that all accumulated changes are published to mapbox.com