markdown-it-synapse-heading/index.js

tag for markdown-it markdown parser.

// Process '## headings'

'use strict';

module.exports = function synapse_heading_plugin(md) {

  function isSpace(code) {
    switch (code) {
      case 0x09:
      case 0x20:
        return true;
    }
    return false;
  }

  function synapse_heading(state, startLine, endLine, silent) {
    var ch, level, tmp, token,
        pos = state.bMarks[startLine] + state.tShift[startLine],
        max = state.eMarks[startLine];

    ch  = state.src.charCodeAt(pos);

    if (ch !== 0x23/* # */ || pos >= max) { return false; }

    // count heading level
    level = 1;
    ch = state.src.charCodeAt(++pos);
    while (ch === 0x23/* # */ && pos < max && level <= 6) {
      level++;
      ch = state.src.charCodeAt(++pos);
    }

    if (level > 6) { return false; }

    if (silent) { return true; }

    // Let's cut tails like '    ###  ' from the end of string

    max = state.skipSpacesBack(max, pos);
    tmp = state.skipCharsBack(max, 0x23, pos); // #
    if (tmp > pos && isSpace(state.src.charCodeAt(tmp - 1))) {
      max = tmp;
    }

    state.line = startLine + 1;

    token        = state.push('synapse_heading_open', 'h' + String(level), 1);
    token.markup = '########'.slice(0, level);
    token.map    = [ startLine, state.line ];
    if (ch !== 0x21/* ! */) {
      token.attrs = [ [ 'toc', 'true' ] ];
    } else {
      token.markup += ch;
      pos++;
    }

    token          = state.push('inline', '', 0);
    token.content  = state.src.slice(pos, max).trim();
    token.map      = [ startLine, state.line ];
    token.children = [];

    token        = state.push('synapse_heading_close', 'h' + String(level), -1);
    token.markup = '########'.slice(0, level);

    return true;
  }
  var rulesCanBeTerminated = [ 'paragraph', 'reference', 'blockquote' ];
  md.block.ruler.after('fence', 'synapse_heading', synapse_heading, { alt: (rulesCanBeTerminated).slice() });
};