From d2e2e760d6e382f2ca0ed912edba51f8c066c299 Mon Sep 17 00:00:00 2001
From: Kuitos <kuitos.lau@gmail.com>
Date: Mon, 12 Oct 2020 18:27:08 +0800
Subject: [PATCH] =?UTF-8?q?=F0=9F=90=9B=20xpath=20return=20undefined=20whi?=
 =?UTF-8?q?le=20the=20dom=20have=20not=20append=20to=20document=20yet=20(#?=
 =?UTF-8?q?991)?=
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---
 src/__tests__/utils.test.ts |  4 ++++
 src/utils.ts                | 13 +++++++++----
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/src/__tests__/utils.test.ts b/src/__tests__/utils.test.ts
index 098f8d2..c2fe06a 100644
--- a/src/__tests__/utils.test.ts
+++ b/src/__tests__/utils.test.ts
@@ -111,4 +111,8 @@ test('should getXPathForElement work well', () => {
     // eslint-disable-next-line max-len
     `/*[name()='HTML' and namespace-uri()='http://www.w3.org/1999/xhtml']/*[name()='BODY' and namespace-uri()='http://www.w3.org/1999/xhtml'][1]/*[name()='ARTICLE' and namespace-uri()='http://www.w3.org/1999/xhtml'][1]/*[name()='DIV' and namespace-uri()='http://www.w3.org/1999/xhtml'][1]/*[name()='DIV' and namespace-uri()='http://www.w3.org/1999/xhtml'][2]`,
   );
+
+  const virtualDOM = document.createElement('div');
+  const xpath1 = getXPathForElement(virtualDOM, document);
+  expect(xpath1).toBeUndefined();
 });
diff --git a/src/utils.ts b/src/utils.ts
index 91603bc..8d3643d 100644
--- a/src/utils.ts
+++ b/src/utils.ts
@@ -142,15 +142,20 @@ export function isEnableScopedCSS(opt: FrameworkConfiguration) {
 /**
  * copy from https://developer.mozilla.org/zh-CN/docs/Using_XPath
  * @param el
- * @param xml
+ * @param document
  */
-export function getXPathForElement(el: Node, xml: Document) {
+export function getXPathForElement(el: Node, document: Document): string | void {
+  // not support that if el not existed in document yet(such as it not append to document before it mounted)
+  if (!document.contains(el)) {
+    return undefined;
+  }
+
   let xpath = '';
   let pos;
   let tmpEle;
   let element = el;
 
-  while (element !== xml.documentElement) {
+  while (element !== document.documentElement) {
     pos = 0;
     tmpEle = element;
     while (tmpEle) {
@@ -168,7 +173,7 @@ export function getXPathForElement(el: Node, xml: Document) {
     element = element.parentNode!;
   }
 
-  xpath = `/*[name()='${xml.documentElement.nodeName}' and namespace-uri()='${
+  xpath = `/*[name()='${document.documentElement.nodeName}' and namespace-uri()='${
     element.namespaceURI === null ? '' : element.namespaceURI
   }']/${xpath}`;
   xpath = xpath.replace(/\/$/, '');