KeyframeEffect 构造函数

KeyframeEffect(
  1. Element? target,
  2. Object? effect,
  3. [Object? options]
)

实现方式

factory KeyframeEffect(Element? target, Object? effect, [Object? options]) {
  if (options != null) {
    return KeyframeEffect._create_1(target, effect, options);
  }
  return KeyframeEffect._create_2(target, effect);
}