web-animations/interfaces/Animation/effect.html

<!DOCTYPE html>
<meta charset=utf-8>
<title>Animation.effect</title>
<link rel="help" href="https://drafts.csswg.org/web-animations/#dom-animation-effect">
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../testcommon.js"></script>
<body>
<div id="log"></div>
<script>
'use strict';

test(t => {
  const anim = new Animation();
  assert_equals(anim.effect, null, 'initial effect is null');

  const newEffect = new KeyframeEffect(createDiv(t), null);
  anim.effect = newEffect;
  assert_equals(anim.effect, newEffect, 'new effect is set');
}, 'effect is set correctly.');

test(t => {
  const div = createDiv(t);
  const animation = div.animate({ left: ['100px', '100px'] },
                                { fill: 'forwards' });
  const effect = animation.effect;

  assert_equals(getComputedStyle(div).left, '100px',
                'animation is initially having an effect');

  animation.effect = null;
  assert_equals(getComputedStyle(div).left, 'auto',
                'animation no longer has an effect');

  animation.effect = effect;
  assert_equals(getComputedStyle(div).left, '100px',
                'animation has an effect again');
}, 'Clearing and setting Animation.effect should update the computed style'
   + ' of the target element');

</script>
</body>