Function toUnloadPromise

src/lifecycles/unload.js:15–96

(appOrParcel)

const appsToUnload = {};

export function toUnloadPromise(appOrParcel) {
  return Promise.resolve().then(() => {
    const unloadInfo = appsToUnload[toName(appOrParcel)];

    if (!unloadInfo) {
      /* No one has called unloadApplication for this app,
       */
      return appOrParcel;
    }

    if (appOrParcel.status === NOT_LOADED) {
      /* This app is already unloaded. We just need to clean up
       * anything that still thinks we need to unload the app.
       */
      finishUnloadingApp(appOrParcel, unloadInfo);
      return appOrParcel;
    }

    if (appOrParcel.status === UNLOADING) {
      /* Both unloadApplication and reroute want to unload this app.
       * It only needs to be done once, though.
       */
      return unloadInfo.promise.then(() => appOrParcel);
    }

    if (
      appOrParcel.status !== NOT_MOUNTED &&
      appOrParcel.status !== LOAD_ERROR
    ) {
      /* The app cannot be unloaded until it is unmounted.
       */
      return appOrParcel;
    }

    let startTime;

    if (__PROFILE__) {
      startTime = performance.now();
    }

    const unloadPromise =
      appOrParcel.status === LOAD_ERROR
        ? Promise.resolve()
        : reasonableTime(appOrParcel, "unload");

    appOrParcel.status = UNLOADING;

    return unloadPromise
      .then(() => {
        if (__PROFILE__) {
          addProfileEntry(
            "application",
            toName(appOrParcel),
            "unload",
            startTime,
            performance.now(),
            true
          );