Script to use Turndown to convert HTML to Python-Markdown-compatible Markdown.

covert_html_to_markdown.js

// npm install turndown turndown-plugin-gfm
var fs = require("fs");
var TurndownService = require("turndown");

var turndownService = new TurndownService({
  headingStyle: "atx",
  bulletListMarker: "-",
  codeBlockStyle: "indent"
  // linkStyle: "referenced",
  // linkReferenceStyle: "shortcut"
});

turndownService.addRule("python-markdown-fence-code", {
  filter: function(node, options) {
    return options.codeBlockStyle === "fenced" && node.nodeName === "PRE";
  },
  replacement: function(content, node, options) {
    var className = node.firstChild.className || "";
    var language = (className.match(/language-(\S+)/) || [null, ""])[1];

    return (
      "\n\n" +
      options.fence +
      language +
      "\n" +
      node.textContent +
      // "\n" +
      options.fence +
      "\n\n"
    );
  }
});

turndownService.addRule("python-markdown-indent-code", {
  filter: function(node, options) {
    return options.codeBlockStyle === "indent" && node.nodeName === "PRE";
  },
  replacement: function(content, node, options) {
    return "\n\n    " + node.textContent.replace(/\n/g, "\n    ");
  }
});

var contents = fs.readFileSync("index.html", "utf8");
var markdown = turndownService.turndown(contents);
fs.writeFileSync("article.md", markdown);