Element.currentPatch reflects current status of patchfor operations

noamr · chromium-wpt-export-bot · commit ca3b40b0dcd1 · 2025-07-20T15:24:47.000-07:00
Added an IDL-exposed PatchStatus, which reflects the status of an ongoing patch operation initiated by <template patchfor>. The exposed interface exposes the detached template element, as well as a promise that resolves when the patching is complete. To be added: rejecting the promise on errors, allowing to abort the patch via the PatchStatus interface. Bug: 431374376 Change-Id: I496447296b3f49e5f197d7e4148e7e8ffda604cb Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6757120 Reviewed-by: Philip Jägenstedt <foolip@chromium.org> Reviewed-by: Noam Rosenthal <nrosenthal@google.com> Commit-Queue: Noam Rosenthal <nrosenthal@google.com> Cr-Commit-Position: refs/heads/main@{#1489336}
diff --git a/html/dom/partial-updates/tentative/current-patch.html b/html/dom/partial-updates/tentative/current-patch.html
@@ -0,0 +1,34 @@
+<!DOCTYPE HTML>
+<meta charset="utf-8" />
+<title>HTML partial updates - reflection via element.currentPatch</title>
+<link rel=help href="https://github.com/WICG/declarative-partial-updates">
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+
+<script>
+promise_test(async t => {
+    const doc = document.implementation.createHTMLDocument();
+    doc.write('<div id="placeholder">Old content</div>');
+    const placeholder = doc.getElementById("placeholder");
+    assert_equals(placeholder.currentPatch, null, "no patch active, currentPatch should be null");
+    doc.write('<template id=patchy patchfor="placeholder">');
+    const {currentPatch} = placeholder;
+    assert_true(currentPatch instanceof PatchStatus);
+    const {finished, source} = currentPatch;
+    assert_true(source instanceof HTMLTemplateElement);
+    assert_equals(source.id, "patchy");
+    let did_finish = false;
+    finished.then((() => {did_finish = true}));
+    await new Promise(resolve => t.step_timeout(resolve, 100));
+    assert_false(did_finish, "we are not finished yet");
+    doc.write("<p>content</p>");
+    await new Promise(resolve => t.step_timeout(resolve, 100));
+    assert_false(did_finish, "we are not finished yet");
+    assert_equals(placeholder.currentPatch, currentPatch);
+    doc.write("</template>");
+    assert_equals(placeholder.currentPatch, null, "template is closed, currentPatch is null");
+    const result = await finished;
+    assert_equals(result, undefined);
+}, "currentPatch lifecycle");
+
+</script>
