showdownjs/src/subParsers/blockGamut.js

/**
 * These are all the transformations that form block-level
 * tags like paragraphs, headers, and list items.
 */
showdown.subParser('blockGamut', function (text, options, globals) {
  'use strict';

  text = showdown.subParser('headers')(text, options, globals);

  // Do Horizontal Rules:
  var key = showdown.subParser('hashBlock')('<hr />', options, globals);
  text = text.replace(/^[ ]{0,2}([ ]?\*[ ]?){3,}[ \t]*$/gm, key);
  text = text.replace(/^[ ]{0,2}([ ]?\-[ ]?){3,}[ \t]*$/gm, key);
  text = text.replace(/^[ ]{0,2}([ ]?\_[ ]?){3,}[ \t]*$/gm, key);

  text = showdown.subParser('lists')(text, options, globals);
  text = showdown.subParser('codeBlocks')(text, options, globals);
  text = showdown.subParser('blockQuotes')(text, options, globals);

  // We already ran _HashHTMLBlocks() before, in Markdown(), but that
  // was to escape raw HTML in the original Markdown source. This time,
  // we're escaping the markup we've just created, so that we don't wrap
  // <p> tags around block-level tags.
  text = showdown.subParser('hashHTMLBlocks')(text, options, globals);
  text = showdown.subParser('paragraphs')(text, options, globals);

  return text;

});