Function transition

core/src/utils/transition/index.ts:30–55

(opts: TransitionOptions)

 * @returns A promise that resolves when the transition is complete.
 */
export const transition = (opts: TransitionOptions): Promise<TransitionResult> => {
  return new Promise((resolve, reject) => {
    writeTask(() => {
      const transitioningInactiveHeader = getIosIonHeader(opts);
      beforeTransition(opts, transitioningInactiveHeader);
      runTransition(opts)
        .then(
          (result) => {
            if (result.animation) {
              result.animation.destroy();
            }
            afterTransition(opts);
            resolve(result);
          },
          (error) => {
            afterTransition(opts);
            reject(error);
          }
        )
        .finally(() => {
          // Ensure that the header is restored to its original state.
          setHeaderTransitionClass(transitioningInactiveHeader, false);
        });
    });
  });
};

const beforeTransition = (opts: TransitionOptions, transitioningInactiveHeader: HTMLElement | null) => {
  const enteringEl = opts.enteringEl;