fix(tocobj): parse permalink if no text

lib/toc_obj.js

@@ -34,13 +34,14 @@ function tocObj(str, options = {}) {
     let text = '';
     for (const element of el.children) {
       const elText = DomUtils.getText(element);
-      // Skip permalink symbol
+      // Skip permalink symbol wrapped in <a>
       // permalink is a single non-word character, word = [a-Z0-9]
       // permalink may be wrapped in whitespace(s)
       if (element.name !== 'a' || !nonWord.test(elText)) {
         text += escapeHTML(elText);
       }
     }
+    if (!text) text = escapeHTML(DomUtils.getText(el));
 
     result.push({ text, id, level });
   }

test/toc_obj.spec.js

@@ -113,6 +113,20 @@ describe('tocObj', () => {
       result[0].text.should.eql('foo');
     });
 
+    it('<a> element - single permalink', () => {
+      const input = '<h1><a>#</a></h1>';
+      const result = tocObj(input);
+
+      result[0].text.should.eql('#');
+    });
+
+    it('<a> element - non-permalink', () => {
+      const input = '<h1><a>a</a> one</h1>';
+      const result = tocObj(input);
+
+      result[0].text.should.eql('a one');
+    });
+
     it('non-permalink <a> element + text', () => {
       const input = [
         '<h1><a>foo</a>bar</h1>',