Function performAppChanges

src/navigation/reroute.js:149–311

()

  }

  function performAppChanges() {
    return Promise.resolve().then(() => {
      // https://github.com/single-spa/single-spa/issues/545
      fireSingleSpaEvent(
        appsThatChanged.length === 0
          ? "before-no-app-change"
          : "before-app-change",
        getCustomEventDetail(true)
      );

      fireSingleSpaEvent(
        "before-routing-event",
        getCustomEventDetail(true, { cancelNavigation })
      );

      return Promise.all(cancelPromises).then((cancelValues) => {
        const navigationIsCanceled = cancelValues.some((v) => v);

        if (navigationIsCanceled) {
          // Change url back to old url, without triggering the normal single-spa reroute
          originalReplaceState.call(
            window.history,
            history.state,
            "",
            oldUrl.substring(location.origin.length)
          );

          // Single-spa's internal tracking of current url needs to be updated after the url change above
          currentUrl = location.href;

          // necessary for the reroute function to know that the current reroute is finished
          appChangeUnderway = false;

          if (__PROFILE__) {
            addProfileEntry(
              "routing",
              "navigationCanceled",
              profilerKind,
              startTime,
              performance.now(),
              true
            );
          }

          // Tell single-spa to reroute again, this time with the url set to the old URL
          return reroute(pendingPromises, eventArguments, true);
        }

        const unloadPromises = appsToUnload.map(toUnloadPromise);

        const unmountUnloadPromises = appsToUnmount
          .map(toUnmountPromise)
          .map((unmountPromise) => unmountPromise.then(toUnloadPromise));

        const allUnmountPromises = unmountUnloadPromises.concat(unloadPromises);

        const unmountAllPromise = Promise.all(allUnmountPromises);