Blitz - WPT: setPathData-mutation-observer.html

wpt / svg / path / interfaces / setPathData-mutation-observer.html

Data from commit:
a50cb89 wpt: run reference-named files which are themselves tests (#836) (2026-09-03)

Subtest	Status	Message
setPathData() fires a MutationObserver record for the d attribute	FAIL	promise_test: Unhandled rejection with value: object "ReferenceError: MutationObserver is not defined"
setPathData([]) fires a MutationObserver record	FAIL	promise_test: Unhandled rejection with value: object "ReferenceError: MutationObserver is not defined"

Enable JavaScript in test iframe

/svg/path/interfaces/setPathData-mutation-observer.html

<!doctype html>
<title>SVGPathElement.setPathData() fires MutationObserver on the d attribute</title>
<link rel="help" href="https://svgwg.org/specs/paths/#__svg__SVGPathData__setPathData">
<link rel="author" title="Virali Purbey" href="mailto:viralipurbey@microsoft.com">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="support/getPathData-helpers.js"></script>

<svg></svg>
<script>
// setPathData() must fire MutationObserver (equivalent to setAttribute('d')).

promise_test(async () => {
  const path = createPath("M 0 0");
  const records = [];
  const observer = new MutationObserver(mutations => {
    for (const m of mutations) {
      records.push({
        type: m.type,
        attributeName: m.attributeName,
        oldValue: m.oldValue,
        newValue: m.target.getAttribute(m.attributeName)
      });
    }
  });
  observer.observe(path, { attributes: true, attributeOldValue: true,
                           attributeFilter: ["d"] });

  path.setPathData([
    { type: "M", values: [0, 0] },
    { type: "L", values: [10, 10] }
  ]);

  await Promise.resolve();  // Flush microtasks so MutationObserver fires.

  observer.disconnect();
  assert_equals(records.length, 1, "exactly one mutation record");
  assert_equals(records[0].type, "attributes");
  assert_equals(records[0].attributeName, "d");
  assert_equals(records[0].oldValue, "M 0 0");
  assert_equals(records[0].newValue, "M 0 0 L 10 10");
}, "setPathData() fires a MutationObserver record for the d attribute");

promise_test(async () => {
  const path = createPath("M 0 0 L 5 5");
  let count = 0;
  const observer = new MutationObserver(mutations => { count += mutations.length; });
  observer.observe(path, { attributes: true, attributeFilter: ["d"] });

  path.setPathData([]);  // Removes the d attribute.

  await Promise.resolve();
  observer.disconnect();
  assert_equals(count, 1, "empty input still fires one record");
  assert_equals(path.getAttribute("d"), null);
}, "setPathData([]) fires a MutationObserver record");
</script>