use diacritics-map lib

(I benchmarked this locally, it was 30x faster than the current code)

also allow users to disable stripping HTML tags with `stripHeadingtags` option

lib/utils.js

@@ -4,7 +4,7 @@
  * Module dependencies
  */
 
-var diacritics = require('./diacritics');
+var diacritics = require('diacritics-map');
 var utils = require('lazy-cache')(require);
 var fn = require;
 require = utils;
@@ -57,19 +57,28 @@ utils.slugify = function(str, options) {
   str = utils.getTitle(str);
   str = utils.stripColor(str);
   str = str.toLowerCase();
+
   // `.split()` is often (but not always) faster than `.replace()`
   str = str.split(' ').join('-');
   str = str.split(/\t/).join('--');
-  str = str.split(/<\/?[^>]+>/).join('');
+  if (options.stripHeadingTags !== false) {
+    str = str.split(/<\/?[^>]+>/).join('');
+  }
   str = str.split(/[|$&`~=\\\/@+*!?({[\]})<>=.,;:'"^]/).join('');
   str = str.split(/[。？！，、；：“”【】（）〔〕［］﹃﹄“ ”‘’﹁﹂—…－～《》〈〉「」]/).join('');
-  str = diacritics.removeDiacritics(str);
+  str = replaceDiacritics(str);
   if (options.num) {
     str += '-' + options.num;
   }
   return str;
 };
 
+function replaceDiacritics(str) {
+  return str.replace(/[À-ž]/g, function(ch) {
+    return diacritics[ch] || ch;
+  });
+}
+
 /**
  * Expose `utils` modules
  */

test/test.js

@@ -100,6 +100,15 @@ describe('options: custom functions:', function() {
     assert.equal(toc('#  Foo <test>').content, '- [Foo](#foo-)');
   });
 
+  it('should not strip HTML tags from headings when `stripHeadingTags` is false', function() {
+    var opts = {stripHeadingTags: false};
+    assert.equal(toc('# <test>Foo', opts).content, '- [Foo](#testfoo)');
+    assert.equal(toc('# <test> Foo', opts).content, '- [Foo](#test-foo)');
+    assert.equal(toc('# <test> Foo ', opts).content, '- [Foo](#test-foo)');
+    assert.equal(toc('# <div> Foo </div>', opts).content, '- [Foo](#div-foo-div)');
+    assert.equal(toc('#  Foo <test>', opts).content, '- [Foo](#foo-test)');
+  });
+
   it('should condense spaces in the heading text', function() {
     var actual = toc('# Some    Article');
     assert.equal(actual.content, '- [Some Article](#some----article)');