Function isLongestAnimation

packages/core/src/animation/utils.ts:329–373

(
  event: AnimationEvent | TransitionEvent,
  nativeElement: HTMLElement,
)

 * @returns
 */
export function isLongestAnimation(
  event: AnimationEvent | TransitionEvent,
  nativeElement: HTMLElement,
): boolean {
  const longestAnimation = longestAnimations.get(nativeElement);
  // If we don't have any record of a longest animation, then we shouldn't
  // block the animationend/transitionend event from doing its work.
  if (longestAnimation === undefined) return true;

  if (nativeElement !== getEventTarget(event)) return false;

  // Distinct CSS animations can share a name. Chrome 151 stable exposes their instance:
  // https://developer.chrome.com/release-notes/151#animation_accessor_on_animation_and_transition_events
  const eventAnimation = (
    event as (AnimationEvent | TransitionEvent) & {readonly animation?: Animation | null}
  ).animation;

  // Compare the event animation's duration instead of retaining the Animation object. This also
  // disambiguates records obtained from computed styles when getAnimations() was empty.
  if (eventAnimation) {
    const eventAnimationDuration = getAnimationDuration(eventAnimation);
    // CSSOM can round serialized times while Web Animations retains more precision. Only reject an
    // event when it is shorter by more than the tolerance so the longest event is not ignored.
    if (
      eventAnimationDuration !== undefined &&
      eventAnimationDuration + ANIMATION_DURATION_TOLERANCE_MS < longestAnimation.duration
    ) {
      return false;
    }
  }

  // Fall back to strings for older browsers.
  if (longestAnimation.animationName !== undefined) {
    return (event as AnimationEvent).animationName === longestAnimation.animationName;
  }

  if (longestAnimation.propertyName !== undefined) {
    return (
      longestAnimation.propertyName === 'all' ||
      (event as TransitionEvent).propertyName === longestAnimation.propertyName
    );
  }

  return false;
}

/**
 * Stores a given animation function in the LView's animation map for later execution