No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp()

In the recent update #flutter has made some changes in order to connect with the firebase, if you wantt to connect your flutter app with firebase you need to initialize the app. So encounter that bug, you need to declare it but where to declare it in a proper way?
In this video you will come to know how to solve this error

[shehannimsara]

your my god brother. U solve my problem. It's huge headache to me. now it's fixed... thnk you thnk you thnk so

[luismeza]

I have the same error but with IONIC :( I don't know how to fix it!

[msantagiulianab]

Thanks.
Problem solved using this video.

[youssoufkanatekanate]

I have follow the step but I am getting the same error on my iOS device simulator android works fine only iOS is giving error

[gnvageesh]

Thanks for the tutorial but, even though I initialize firebase in the flutter app, it says the same error

[ganeshhurgule]

Error: [core/not-initialized] Firebase has not been correctly initialized. Have you added the Firebase import scripts to your index.html file?
this is my error bro please solve i spend lot of time to solved but i could not able to solved it