fix: ensure element has a parent

refs #19

src/selector-nth-of-type.js

@@ -7,10 +7,14 @@ import {getTagSelector} from './selector-tag';
  */
 export function getNthOfTypeSelector (element) {
   const tag = getTagSelector(element)[0];
-  const siblings = element.parentElement.querySelectorAll(tag);
-  for (let i = 0; i < siblings.length; i++) {
-    if (siblings[i] === element) {
-      return [`${tag}:nth-of-type(${i + 1})`];
+  const parentElement = element.parentElement;
+
+  if (parentElement) {
+    const siblings = parentElement.querySelectorAll(tag);
+    for (let i = 0; i < siblings.length; i++) {
+      if (siblings[i] === element) {
+        return [`${tag}:nth-of-type(${i + 1})`];
+      }
     }
   }
 

test/selector-nth-of-type.spec.js

@@ -40,4 +40,26 @@ describe('selector - nth-of-type', function () {
     assert.equal(result, 'p:nth-of-type(2)');
   });
 
+  it('should not throw for element without parent', function () {
+    const element = document.createElement('div');
+    const fn = function () {
+      getCssSelector(element, {
+        selectors: ['nthoftype'],
+        root,
+      });
+    };
+    assert.doesNotThrow(fn);
+  });
+
+  it('should not throw for element directly in document', function () {
+    const element = document.querySelector('html');
+    const fn = function () {
+      getCssSelector(element, {
+        selectors: ['nthoftype'],
+        root,
+      });
+    };
+    assert.doesNotThrow(fn);
+  });
+
 });