Document patching: initial support

noamr · chromium-wpt-export-bot · commit 530f687b27f3 · 2025-07-14T13:16:33.000-07:00
Add runtime flag + very basic support for <template patchfor> Chromestatus: https://chromestatus.com/feature/5111042975465472?gate=5122079833456640 Bug: 431374376 Change-Id: I6cb86725c51fc4416516c628e153493bc4073228 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6732978 Reviewed-by: Philip Jägenstedt <foolip@chromium.org> Commit-Queue: Noam Rosenthal <nrosenthal@google.com> Cr-Commit-Position: refs/heads/main@{#1486491}
diff --git a/html/dom/partial-updates/tentative/template-patchfor-reverse.html b/html/dom/partial-updates/tentative/template-patchfor-reverse.html
@@ -0,0 +1,16 @@
+<!DOCTYPE HTML>
+<meta charset="utf-8" />
+<title>HTML partial updates: patch should appear after its target</title>
+<link rel=help href="https://github.com/WICG/declarative-partial-updates">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<template patchfor="placeholder">New content</template>
+<div id="placeholder">Old content</div>
+<script>
+test(() => {
+    assert_equals(document.querySelector("#placeholder").innerText, "Old content");
+    assert_equals(document.querySelector("template[patchfor=placeholder]").content.textContent, "New content",
+    "<template patchfor> without a match should parse normally");
+}, "<template patchfor> should apply directly to its target");
+</script>
diff --git a/html/dom/partial-updates/tentative/template-patchfor.html b/html/dom/partial-updates/tentative/template-patchfor.html
@@ -0,0 +1,30 @@
+<!DOCTYPE HTML>
+<meta charset="utf-8" />
+<title>HTML partial updates</title>
+<link rel=help href="https://github.com/WICG/declarative-partial-updates">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<div id="placeholder">Old content</div>
+<template patchfor="placeholder">New content</template>
+<script>
+test(() => {
+    assert_equals(document.querySelector("#placeholder").innerText, "New content");
+    assert_equals(document.querySelector("template[patchfor]"), null, "<template patchfor> with a match should not attach");
+}, "<template patchfor> should apply directly to its target");
+
+test(() => {
+    const doc = document.implementation.createHTMLDocument();
+    doc.write('<div id="placeholder">Old content</div>');
+    assert_equals(doc.querySelector("#placeholder").innerText, "Old content");
+    doc.write('<template patchfor="placeholder">');
+    assert_equals(doc.querySelector("template"), null);
+    assert_equals(doc.querySelector("#placeholder").innerText, "");
+    doc.write('New');
+    assert_equals(doc.querySelector("#placeholder").innerText, "New");
+    doc.write(' content</template>');
+    assert_equals(doc.querySelector("#placeholder").innerText, "New content");
+    assert_equals(doc.querySelector("template"), null);
+}, "<template patchfor> should work when chunked");
+
+</script>
