feat(text selector): pierce shadow roots (#1619)

docs/selectors.md

@@ -76,6 +76,8 @@ Text engine finds an element that contains a text node with passed text. Example
 - Text body can be escaped with double quotes for precise matching, insisting on exact match, including specified whitespace and case. This means `text="Login "` will only match `<button>Login </button>` with exactly one space after "Login".
 - Text body can also be a JavaScript-like regex wrapped in `/` symbols. This means `text=/^\\s*Login$/i` will match `<button> loGIN</button>` with any number of spaces before "Login" and no spaces after.
 
+> **NOTE** Text engine searches for elements inside open shadow roots, but not inside closed shadow roots or iframes.
+
 > **NOTE** Malformed selector starting with `"` is automatically transformed to text selector. For example, Playwright converts `page.click('"Login"')` to `page.click('text="Login"')`.
 
 ### id, data-testid, data-test-id, data-test

src/injected/textSelectorEngine.ts

@@ -28,41 +28,19 @@ export const TextEngine: SelectorEngine = {
           continue;
         if (text.match(/^\s*[a-zA-Z0-9]+\s*$/) && TextEngine.query(root, text.trim()) === targetElement)
           return text.trim();
-        if (TextEngine.query(root, JSON.stringify(text)) === targetElement)
+        if (queryInternal(root, createMatcher(JSON.stringify(text))) === targetElement)
           return JSON.stringify(text);
       }
     }
   },
 
   query(root: SelectorRoot, selector: string): Element | undefined {
-    const document = root instanceof Document ? root : root.ownerDocument;
+    return queryInternal(root, createMatcher(selector));
-    if (!document)
-      return;
-    const matcher = createMatcher(selector);
-    const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT);
-    while (walker.nextNode()) {
-      const node = walker.currentNode;
-      const element = node.parentElement;
-      const text = node.nodeValue;
-      if (element && text && matcher(text))
-        return element;
-    }
   },
 
   queryAll(root: SelectorRoot, selector: string): Element[] {
     const result: Element[] = [];
-    const document = root instanceof Document ? root : root.ownerDocument;
+    queryAllInternal(root, createMatcher(selector), result);
-    if (!document)
-      return result;
-    const matcher = createMatcher(selector);
-    const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT);
-    while (walker.nextNode()) {
-      const node = walker.currentNode;
-      const element = node.parentElement;
-      const text = node.nodeValue;
-      if (element && text && matcher(text))
-        result.push(element);
-    }
     return result;
   }
 };
@@ -81,3 +59,48 @@ function createMatcher(selector: string): Matcher {
   selector = selector.trim().toLowerCase();
   return text => text.toLowerCase().includes(selector);
 }
+
+function queryInternal(root: SelectorRoot, matcher: Matcher): Element | undefined {
+  const document = root instanceof Document ? root : root.ownerDocument!;
+  const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT | NodeFilter.SHOW_ELEMENT);
+  const shadowRoots = [];
+  while (walker.nextNode()) {
+    const node = walker.currentNode;
+    if (node.nodeType === Node.ELEMENT_NODE) {
+      const element = node as Element;
+      if (element.shadowRoot)
+        shadowRoots.push(element.shadowRoot);
+    } else {
+      const element = node.parentElement;
+      const text = node.nodeValue;
+      if (element && element.nodeName !== 'SCRIPT' && element.nodeName !== 'STYLE' && text && matcher(text))
+        return element;
+    }
+  }
+  for (const shadowRoot of shadowRoots) {
+    const element = queryInternal(shadowRoot, matcher);
+    if (element)
+      return element;
+  }
+}
+
+function queryAllInternal(root: SelectorRoot, matcher: Matcher, result: Element[]) {
+  const document = root instanceof Document ? root : root.ownerDocument!;
+  const walker = document.createTreeWalker(root, NodeFilter.SHOW_TEXT | NodeFilter.SHOW_ELEMENT);
+  const shadowRoots = [];
+  while (walker.nextNode()) {
+    const node = walker.currentNode;
+    if (node.nodeType === Node.ELEMENT_NODE) {
+      const element = node as Element;
+      if (element.shadowRoot)
+        shadowRoots.push(element.shadowRoot);
+    } else {
+      const element = node.parentElement;
+      const text = node.nodeValue;
+      if (element && element.nodeName !== 'SCRIPT' && element.nodeName !== 'STYLE' && text && matcher(text))
+        result.push(element);
+    }
+  }
+  for (const shadowRoot of shadowRoots)
+    queryAllInternal(shadowRoot, matcher, result);
+}

test/queryselector.spec.js

@@ -540,6 +540,13 @@ module.exports.describe = function({testRunner, expect, playwright, FFOX, CHROMI
       expect(await page.$eval(`text=with`, e => e.outerHTML)).toBe('<div>textwithsubstring</div>');
       expect(await page.$(`text="with"`)).toBe(null);
     });
+
+    it('should work for open shadow roots', async({page, server}) => {
+      await page.goto(server.PREFIX + '/deep-shadow.html');
+      expect(await page.$eval(`text=root1`, e => e.outerHTML)).toBe('<span>Hello from root1</span>');
+      expect(await page.$eval(`text=root2`, e => e.outerHTML)).toBe('<span>Hello from root2</span>');
+      expect(await page.$eval(`text=root3`, e => e.outerHTML)).toBe('<span>Hello from root3</span>');
+    });
   });
 
   describe('selectors.register', () => {