web-animations/interfaces/KeyframeEffect/target.html

<!DOCTYPE html>
<meta charset=utf-8>
<title>KeyframeEffect.target and .pseudoElement</title>
<link rel="help"
  href="https://drafts.csswg.org/web-animations/#dom-keyframeeffect-target">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../testcommon.js"></script>
<style>
  .before::before {content: 'foo'; display: inline-block;}
  .after::after {content: 'bar'; display: inline-block;}
  .pseudoa::before, .pseudoc::before {margin-left: 10px;}
  .pseudob::before, .pseudoc::after {margin-left: 20px;}
</style>
<body>
<div id="log"></div>
<script>
'use strict';

const gKeyFrames = { 'marginLeft': ['0px', '100px'] };

test(t => {
  const div = createDiv(t);
  const effect = new KeyframeEffect(null, gKeyFrames, 100 * MS_PER_SEC);
  effect.target = div;

  const anim = new Animation(effect, document.timeline);
  anim.play();

  anim.currentTime = 50 * MS_PER_SEC;
  assert_equals(getComputedStyle(div).marginLeft, '50px',
                'Value at 50% progress');
}, 'Test setting target before constructing the associated animation');

test(t => {
  const div = createDiv(t);
  div.style.marginLeft = '10px';
  const effect = new KeyframeEffect(null, gKeyFrames, 100 * MS_PER_SEC);
  const anim = new Animation(effect, document.timeline);
  anim.play();

  anim.currentTime = 50 * MS_PER_SEC;
  assert_equals(getComputedStyle(div).marginLeft, '10px',
                'Value at 50% progress before setting new target');
  effect.target = div;
  assert_equals(getComputedStyle(div).marginLeft, '50px',
                'Value at 50% progress after setting new target');
}, 'Test setting target from null to a valid target');

test(t => {
  const div = createDiv(t);
  div.style.marginLeft = '10px';
  const anim = div.animate(gKeyFrames, 100 * MS_PER_SEC);

  anim.currentTime = 50 * MS_PER_SEC;
  assert_equals(getComputedStyle(div).marginLeft, '50px',
                'Value at 50% progress before clearing the target')

  anim.effect.target = null;
  assert_equals(getComputedStyle(div).marginLeft, '10px',
                'Value after clearing the target')
}, 'Test setting target from a valid target to null');

test(t => {
  const a = createDiv(t);
  const b = createDiv(t);
  a.style.marginLeft = '10px';
  b.style.marginLeft = '20px';
  const anim = a.animate(gKeyFrames, 100 * MS_PER_SEC);

  anim.currentTime = 50 * MS_PER_SEC;
  assert_equals(getComputedStyle(a).marginLeft, '50px',
                'Value of 1st element (currently targeted) before ' +
                'changing the effect target');
  assert_equals(getComputedStyle(b).marginLeft, '20px',
                'Value of 2nd element (currently not targeted) before ' +
                'changing the effect target');
  anim.effect.target = b;
  assert_equals(getComputedStyle(a).marginLeft, '10px',
                'Value of 1st element (currently not targeted) after ' +
                'changing the effect target');
  assert_equals(getComputedStyle(b).marginLeft, '50px',
                'Value of 2nd element (currently targeted) after ' +
                'changing the effect target');

  // This makes sure the animation property is changed correctly on new
  // targeted element.
  anim.currentTime = 75 * MS_PER_SEC;
  assert_equals(getComputedStyle(b).marginLeft, '75px',
                'Value of 2nd target (currently targeted) after ' +
                'changing the animation current time.');
}, 'Test setting target from a valid target to another target');

promise_test(async t => {
  const animation = createDiv(t).animate(
    { opacity: 0 },
    { duration: 1, fill: 'forwards' }
  );

  const foreignElement
    = document.createElementNS('http://example.org/test', 'test');
  document.body.appendChild(foreignElement);
  t.add_cleanup(() => {
    foreignElement.remove();
  });

  animation.effect.target = foreignElement;

  // Wait a frame to make sure nothing bad happens when the UA tries to update
  // style.
  await waitForNextFrame();
}, 'Target element can be set to a foreign element');

// Pseudo-element tests
// (testing target and pseudoElement in these cases)
// Since blink uses separate code paths for handling pseudo-element styles
// depending on whether content is set (putting the pseudo-element in the layout),
// we run tests on both cases.
for (const hasContent of [true, false]){
  test(t => {
    const d = createDiv(t);
    d.classList.add('pseudoa');
    if (hasContent) {
      d.classList.add('before');
    }

    const effect = new KeyframeEffect(null, gKeyFrames, 100 * MS_PER_SEC);
    const anim = new Animation(effect, document.timeline);
    anim.play();

    anim.currentTime = 50 * MS_PER_SEC;
    assert_equals(getComputedStyle(d, '::before').marginLeft, '10px',
                  'Value at 50% progress before setting new target');
    effect.target = d;
    effect.pseudoElement = '::before';

    assert_equals(effect.target, d, "Target element is set correctly");
    assert_equals(effect.pseudoElement, '::before', "Target pseudo-element set correctly");
    assert_equals(getComputedStyle(d, '::before').marginLeft, '50px',
                  'Value at 50% progress after setting new target');
  }, "Change target from null to " + (hasContent ? "an existing" : "a non-existing") +
     " pseudoElement setting target first.");

  test(t => {
    const d = createDiv(t);
    d.classList.add('pseudoa');
    if (hasContent) {
      d.classList.add('before');
    }

    const effect = new KeyframeEffect(null, gKeyFrames, 100 * MS_PER_SEC);
    const anim = new Animation(effect, document.timeline);
    anim.play();

    anim.currentTime = 50 * MS_PER_SEC;
    assert_equals(getComputedStyle(d, '::before').marginLeft, '10px',
                  'Value at 50% progress before setting new target');
    effect.pseudoElement = '::before';
    effect.target = d;

    assert_equals(effect.target, d, "Target element is set correctly");
    assert_equals(effect.pseudoElement, '::before', "Target pseudo-element set correctly");
    assert_equals(getComputedStyle(d, '::before').marginLeft, '50px',
                  'Value at 50% progress after setting new target');
  }, "Change target from null to " + (hasContent ? "an existing" : "a non-existing") +
     " pseudoElement setting pseudoElement first.");

  test(t => {
    const d = createDiv(t);
    d.classList.add('pseudoa');
    if (hasContent) {
      d.classList.add('before');
    }
    const anim = d.animate(gKeyFrames, {duration: 100 * MS_PER_SEC, pseudoElement: '::before'});

    anim.currentTime = 50 * MS_PER_SEC;
    anim.effect.pseudoElement = null;
    assert_equals(anim.effect.target, d,
                  "Animation targets specified element (target element)");
    assert_equals(anim.effect.pseudoElement, null,
                  "Animation targets specified element (null pseudo-selector)");
    assert_equals(getComputedStyle(d, '::before').marginLeft, '10px',
                  'Value of 1st element (currently not targeted) after ' +
                  'changing the effect target');
    assert_equals(getComputedStyle(d).marginLeft, '50px',
                  'Value of 2nd element (currently targeted) after ' +
                  'changing the effect target');
  }, "Change target from " + (hasContent ? "an existing" : "a non-existing") + " pseudo-element to the originating element.");

  for (const prevHasContent of [true, false]) {
    test(t => {
      const a = createDiv(t);
      a.classList.add('pseudoa');
      const b = createDiv(t);
      b.classList.add('pseudob');
      if (prevHasContent) {
        a.classList.add('before');
      }
      if (hasContent) {
        b.classList.add('before');
      }

      const anim = a.animate(gKeyFrames, {duration: 100 * MS_PER_SEC, pseudoElement: '::before'});

      anim.currentTime = 50 * MS_PER_SEC;
      anim.effect.target = b;
      assert_equals(anim.effect.target, b,
                    "Animation targets specified pseudo-element (target element)");
      assert_equals(anim.effect.pseudoElement, '::before',
                    "Animation targets specified pseudo-element (pseudo-selector)");
      assert_equals(getComputedStyle(a, '::before').marginLeft, '10px',
                    'Value of 1st element (currently not targeted) after ' +
                    'changing the effect target');
      assert_equals(getComputedStyle(b, '::before').marginLeft, '50px',
                    'Value of 2nd element (currently targeted) after ' +
                    'changing the effect target');
    }, "Change target from " + (prevHasContent ? "an existing" : "a non-existing") +
        " to a different " + (hasContent ? "existing" : "non-existing") +
        " pseudo-element by setting target.");

    test(t => {
      const d = createDiv(t);
      d.classList.add('pseudoc');
      if (prevHasContent) {
        d.classList.add('before');
      }
      if (hasContent) {
        d.classList.add('after');
      }

      const anim = d.animate(gKeyFrames, {duration: 100 * MS_PER_SEC, pseudoElement: '::before'});

      anim.currentTime = 50 * MS_PER_SEC;
      anim.effect.pseudoElement = '::after';
      assert_equals(anim.effect.target, d,
                    "Animation targets specified pseudo-element (target element)");
      assert_equals(anim.effect.pseudoElement, '::after',
                    "Animation targets specified pseudo-element (pseudo-selector)");
      assert_equals(getComputedStyle(d, '::before').marginLeft, '10px',
                    'Value of 1st element (currently not targeted) after ' +
                    'changing the effect target');
      assert_equals(getComputedStyle(d, '::after').marginLeft, '50px',
                    'Value of 2nd element (currently targeted) after ' +
                    'changing the effect target');
    }, "Change target from " + (prevHasContent ? "an existing" : "a non-existing") +
        " to a different " + (hasContent ? "existing" : "non-existing") +
        " pseudo-element by setting pseudoElement.");
  }
}

for (const pseudo of [
  '',
  'before',
  ':abc',
  '::abc',
  '::placeholder',
]) {
  test(t => {
    const effect = new KeyframeEffect(null, gKeyFrames, 100 * MS_PER_SEC);
    assert_throws_dom("SyntaxError", () => effect.pseudoElement = pseudo );
  }, `Changing pseudoElement to a non-null invalid pseudo-selector ` +
     `'${pseudo}' throws a SyntaxError`);
}

</script>
</body>