renderer.js

'use strict';

const { promisify } = require('util');
const marked = promisify(require('marked'));
const stripIndent = require('strip-indent');
const { encodeURL, highlight, slugize, stripHTML, url_for, isExternalLink } = require('hexo-util');
const MarkedRenderer = marked.Renderer;
const { parse } = require('url');

const anchorId = (str, transformOption) => {
  return slugize(str.trim(), {transform: transformOption});
};

class Renderer extends MarkedRenderer {
  constructor() {
    super();
    this._headingId = {};
  }

  // Add id attribute to headings
  heading(text, level) {
    if (!this.options.headerIds) {
      return `<h${level}>${text}</h${level}>`;
    }
    const transformOption = this.options.modifyAnchors;
    let id = anchorId(stripHTML(text), transformOption);
    const headingId = this._headingId;

    // Add a number after id if repeated
    if (headingId[id]) {
      id += `-${headingId[id]++}`;
    } else {
      headingId[id] = 1;
    }

    // add headerlink
    return `<h${level} id="${id}"><a href="#${id}" class="headerlink" title="${stripHTML(text)}"></a>${text}</h${level}>`;
  }

  // Support AutoLink option
  link(href, title, text) {
    const { options } = this;
    const { external_link } = options;
    if (options.sanitizeUrl) {
      if (href.startsWith('javascript:') || href.startsWith('vbscript:') || href.startsWith('data:')) {
        href = '';
      }
    }
    if (!options.autolink && href === text && title == null) {
      return href;
    }

    let out = `<a href="${encodeURL(href)}"`;
    if (title) {
      out += ` title="${title}"`;
    }
    if (external_link) {
      const target = ' target="_blank"';
      const noopener = ' rel="noopener"';
      const nofollowTag = ' rel="noopener external nofollow noreferrer"';
      if (isExternalLink(href, options.config.url, external_link.exclude)) {
        if (external_link.enable && external_link.nofollow) {
          out += target + nofollowTag;
        } else if (external_link.enable) {
          out += target + noopener;
        } else if (external_link.nofollow) {
          out += nofollowTag;
        }
      }
    }

    out += `>${text}</a>`;
    return out;
  }

  // Support Basic Description Lists
  paragraph(text) {
    const dlTest = /(?:^|\s)(\S.+)<br>:\s+(\S.+)/;
    const dl = '<dl><dt>$1</dt><dd>$2</dd></dl>';
    if (dlTest.test(text)) {
      return text.replace(dlTest, dl);
    }
    return `<p>${text}</p>\n`;
  }

  // Prepend root to image path
  image(href, title, text) {
    const { options } = this;

    if (!parse(href).hostname && !options.config.relative_link
      && options.prependRoot) {
      href = url_for.call(options, href);
    }

    let out = `<img src="${encodeURL(href)}"`;
    if (text) out += ` alt="${text}"`;
    if (title) out += ` title="${title}"`;

    out += '>';
    return out;
  }
}

marked.setOptions({
  langPrefix: '',
  highlight(code, lang) {
    return highlight(stripIndent(code), {
      lang,
      gutter: false,
      wrap: false
    });
  }
});

module.exports = async function(data, options) {
  const siteCfg = Object.assign({}, {
    config: {
      url: this.config.url,
      root: this.config.root,
      relative_link: this.config.relative_link
    }
  });

  // exec filter to extend renderer.
  const renderer = new Renderer();
  await this.execFilter('marked:renderer', renderer, {context: this});

  const result = await marked(data.text, Object.assign({
    renderer
  }, this.config.marked, options, siteCfg));
  return result;
};