beforeDestroy Not Working?

I’ve got this bit of code here that I’m trying to run. It SHOULD print to the console log on beforeDestroy but isn’t. I’ve set my console logs to “Preserve Log” but it isn’t printing to the console when I refresh the page to restart the app using Google Chrome.

  mounted() {
  this.$f7ready(() => {
    unSubscribe = auth.onAuthStateChanged((user) => {
      if (user) {
        this.$setState({ userIsLoggedIn: true });
      } else {
beforeDestroy() { console.log('Before Destroy'); }

in this case, it will not be called

@shastox Thanks for the response! In that case, how can it be tested to ensure what I am wanting to accomplish in beforeDestroy is properly completed?