markdownlint/lib/md003.js

// @ts-check

"use strict";

const { addErrorDetailIf } = require("../helpers");
const { filterByTypes, getHeadingLevel, getHeadingStyle } =
  require("../helpers/micromark.cjs");

// eslint-disable-next-line jsdoc/valid-types
/** @type import("./markdownlint").Rule */
module.exports = {
  "names": [ "MD003", "heading-style" ],
  "description": "Heading style",
  "tags": [ "headings" ],
  "parser": "micromark",
  "function": function MD003(params, onError) {
    let style = String(params.config.style || "consistent");
    const headings = filterByTypes(
      params.parsers.micromark.tokens,
      [ "atxHeading", "setextHeading" ]
    );
    for (const heading of headings) {
      const styleForToken = getHeadingStyle(heading);
      if (style === "consistent") {
        style = styleForToken;
      }
      if (styleForToken !== style) {
        const h12 = getHeadingLevel(heading) <= 2;
        const setextWithAtx =
          (style === "setext_with_atx") &&
            ((h12 && (styleForToken === "setext")) ||
            (!h12 && (styleForToken === "atx")));
        const setextWithAtxClosed =
          (style === "setext_with_atx_closed") &&
            ((h12 && (styleForToken === "setext")) ||
            (!h12 && (styleForToken === "atx_closed")));
        if (!setextWithAtx && !setextWithAtxClosed) {
          let expected = style;
          if (style === "setext_with_atx") {
            expected = h12 ? "setext" : "atx";
          } else if (style === "setext_with_atx_closed") {
            expected = h12 ? "setext" : "atx_closed";
          }
          addErrorDetailIf(
            onError,
            heading.startLine,
            expected,
            styleForToken
          );
        }
      }
    }
  }
};