markdown-it/lib/rules_core/abbr2.js

// Enclose abbreviations in <abbr> tags
//
'use strict';


var PUNCT_CHARS = ' \n()[]\'".,!?-';


// from Google closure library
// http://closure-library.googlecode.com/git-history/docs/local_closure_goog_string_string.js.source.html#line1021
function regEscape(s) {
  return s.replace(/([-()\[\]{}+?*.$\^|,:#<!\\])/g, '\\$1');
}


module.exports = function abbr2(state) {
  var i, j, l, tokens, token, text, nodes, pos, level, reg, m, regText,
      blockTokens = state.tokens;

  if (!state.env.abbreviations) { return; }
  if (!state.env.abbrRegExp) {
    regText = '(^|[' + PUNCT_CHARS.split('').map(regEscape).join('') + '])'
            + '(' + Object.keys(state.env.abbreviations).map(function (x) {
                      return x.substr(1);
                    }).sort(function (a, b) {
                      return b.length - a.length;
                    }).map(regEscape).join('|') + ')'
            + '($|[' + PUNCT_CHARS.split('').map(regEscape).join('') + '])';
    state.env.abbrRegExp = new RegExp(regText, 'g');
  }
  reg = state.env.abbrRegExp;

  for (j = 0, l = blockTokens.length; j < l; j++) {
    if (blockTokens[j].type !== 'inline') { continue; }
    tokens = blockTokens[j].children;

    // We scan from the end, to keep position when new tags added.
    for (i = tokens.length - 1; i >= 0; i--) {
      token = tokens[i];
      if (token.type !== 'text') { continue; }

      pos = 0;
      text = token.content;
      reg.lastIndex = 0;
      level = token.level;
      nodes = [];

      while ((m = reg.exec(text))) {
        if (reg.lastIndex > pos) {
          nodes.push({
            type: 'text',
            content: text.slice(pos, m.index + m[1].length),
            level: level
          });
        }

        nodes.push({
          type: 'abbr_open',
          title: state.env.abbreviations[':' + m[2]],
          level: level++
        });
        nodes.push({
          type: 'text',
          content: m[2],
          level: level
        });
        nodes.push({
          type: 'abbr_close',
          level: --level
        });
        pos = reg.lastIndex - m[3].length;
      }

      if (!nodes.length) { continue; }

      if (pos < text.length) {
        nodes.push({
          type: 'text',
          content: text.slice(pos),
          level: level
        });
      }

      // replace current node
      blockTokens[j].children = tokens = [].concat(tokens.slice(0, i), nodes, tokens.slice(i + 1));
    }
  }
};