Fix handling comments when template has no tags (#3008)

Author: simplesmiler

src/parsers/template.js

@@ -76,6 +76,7 @@ function isRealTemplate (node) {
 
 const tagRE = /<([\w:-]+)/
 const entityRE = /&#?\w+?;/
+const commentRE = /<!--/
 
 /**
  * Convert a string template to a DocumentFragment.
@@ -100,8 +101,9 @@ function stringToFragment (templateString, raw) {
   var frag = document.createDocumentFragment()
   var tagMatch = templateString.match(tagRE)
   var entityMatch = entityRE.test(templateString)
+  var commentMatch = commentRE.test(templateString)
 
-  if (!tagMatch && !entityMatch) {
+  if (!tagMatch && !entityMatch && !commentMatch) {
     // text only, return a single text node.
     frag.appendChild(
       document.createTextNode(templateString)

test/unit/specs/parsers/template_spec.js

@@ -23,6 +23,13 @@ describe('Template Parser', function () {
     expect(res.firstChild.nodeType).toBe(3) // Text node
   })
 
+  it('should work if the template string doesn\'t contain tags but contains comments', function () {
+    var res = parse('<!-- yo -->hello<!-- yo -->')
+    expect(res.childNodes.length).toBe(1)
+    expect(res.firstChild.nodeType).toBe(3) // text node
+    expect(res.firstChild.nodeValue).toBe('hello')
+  })
+
   it('should handle string that contains html entities', function () {
     var res = parse('foo&lt;bar')
     expect(res.nodeType).toBe(11)