fix(client): ensure head and body with newline are parsed correctly

Fixes #317

remarkablemark/html-react-parser#624

lib/client/domparser.js

@@ -3,8 +3,9 @@ var HTML = 'html';
 var HEAD = 'head';
 var BODY = 'body';
 var FIRST_TAG_REGEX = /<([a-zA-Z]+[0-9]?)/; // e.g., <h1>
-var HEAD_TAG_REGEX = /<head.*>/i;
-var BODY_TAG_REGEX = /<body.*>/i;
+// match-all-characters in case of newlines (DOTALL)
+var HEAD_TAG_REGEX = /<head[^]*>/i;
+var BODY_TAG_REGEX = /<body[^]*>/i;
 
 // falls back to `parseFromString` if `createHTMLDocument` cannot be used
 var parseFromDocument = function () {
@@ -63,7 +64,8 @@ if (document.implementation) {
    */
   parseFromDocument = function (html, tagName) {
     if (tagName) {
-      doc.documentElement.getElementsByTagName(tagName)[0].innerHTML = html;
+      var element = doc.documentElement.querySelector(tagName);
+      element.innerHTML = html;
       return doc;
     }
 
@@ -118,24 +120,25 @@ function domparser(html) {
       // the created document may come with filler head/body elements,
       // so make sure to remove them if they don't actually exist
       if (!HEAD_TAG_REGEX.test(html)) {
-        element = doc.getElementsByTagName(HEAD)[0];
+        element = doc.querySelector(HEAD);
         if (element) {
           element.parentNode.removeChild(element);
         }
       }
 
       if (!BODY_TAG_REGEX.test(html)) {
-        element = doc.getElementsByTagName(BODY)[0];
+        element = doc.querySelector(BODY);
         if (element) {
           element.parentNode.removeChild(element);
         }
       }
 
-      return doc.getElementsByTagName(HTML);
+      return doc.querySelectorAll(HTML);
 
     case HEAD:
     case BODY:
-      elements = parseFromDocument(html).getElementsByTagName(firstTagName);
+      doc = parseFromDocument(html);
+      elements = doc.querySelectorAll(firstTagName);
 
       // if there's a sibling element, then return both elements
       if (BODY_TAG_REGEX.test(html) && HEAD_TAG_REGEX.test(html)) {
@@ -148,9 +151,8 @@ function domparser(html) {
       if (parseFromTemplate) {
         return parseFromTemplate(html);
       }
-
-      return parseFromDocument(html, BODY).getElementsByTagName(BODY)[0]
-        .childNodes;
+      element = parseFromDocument(html, BODY).querySelector(BODY);
+      return element.childNodes;
   }
 }