@nuxtjs/mdc/dist/runtime/parser/compiler.js

Nuxt MDC module

import { toString } from "hast-util-to-string";
import Slugger from "github-slugger";
import { validateProps } from "./utils/props.js";
export function compileHast(options = {}) {
  const slugs = new Slugger();
  function compileToJSON(node, parent) {
    if (node.type === "root") {
      return {
        type: "root",
        children: node.children.map((child) => compileToJSON(child, node)).filter(Boolean)
      };
    }
    const position = node.position?.start?.offset && node.position?.end?.offset ? {
      start: node.position.start.offset,
      end: node.position.end.offset
    } : void 0;
    if (node.type === "element") {
      if (node.tagName === "p" && node.children.every((child) => child.type === "text" && /^\s*$/.test(child.value))) {
        return null;
      }
      if (node.tagName === "li") {
        let hasPreviousParagraph = false;
        node.children = node.children?.flatMap((child) => {
          if (child.type === "element" && child.tagName === "p") {
            if (hasPreviousParagraph) {
              child.children.unshift({
                type: "element",
                tagName: "br",
                properties: {},
                children: []
              });
            }
            hasPreviousParagraph = true;
            return child.children;
          }
          return child;
        });
      }
      if (node.tagName?.match(/^h\d$/)) {
        node.properties = node.properties || {};
        node.properties.id = String(node.properties?.id || slugs.slug(toString(node))).replace(/-+/g, "-").replace(/^-|-$/g, "").replace(/^(\d)/, "_$1");
      }
      if (node.tagName === "component-slot") {
        node.tagName = "template";
      }
      const children = (node.tagName === "template" && node.content?.children.length ? node.content.children : node.children).map((child) => compileToJSON(child, node)).filter(Boolean);
      const result = {
        type: "element",
        tag: node.tagName,
        props: validateProps(node.tagName, node.properties),
        children
      };
      if (options.keepPosition) {
        result.position = position;
      }
      return result;
    }
    if (node.type === "text") {
      if (!/^\n+$/.test(node.value || "") || parent?.properties?.emptyLinePlaceholder) {
        return options.keepPosition ? { type: "text", value: node.value, position } : { type: "text", value: node.value };
      }
    }
    if (options.keepComments && node.type === "comment") {
      return options.keepPosition ? { type: "comment", value: node.value, position } : { type: "comment", value: node.value };
    }
    return null;
  }
  this.Compiler = (tree) => {
    const body = compileToJSON(tree);
    let excerpt = void 0;
    const excerptIndex = tree.children.findIndex((node) => node.type === "comment" && node.value?.trim() === "more");
    if (excerptIndex !== -1) {
      excerpt = compileToJSON({
        type: "root",
        children: tree.children.slice(0, excerptIndex)
      });
      if (excerpt.children.find((node) => node.type === "element" && node.tag === "pre")) {
        const lastChild = body.children[body.children.length - 1];
        if (lastChild.type === "element" && lastChild.tag === "style") {
          excerpt.children.push(lastChild);
        }
      }
    }
    body.children = (body.children || []).filter((child) => child.type !== "text");
    return {
      body,
      excerpt
    };
  };
}