Today i tried to make my app ready for my website so i ran this command:

 npm run build --prod

and then i got this long error on my terminal:

[00:00:50]  Error: Type QuestionMessagePage in
            pages/question-message/question-message.ts is part
            of the declarations of 2 modules:
            AppModule in app/app.module.ts and
            QuestionMessageModule in pages/question-message/question-message.module.ts!
            Please consider moving QuestionMessagePage in
            pages/question-message/question-message.ts to a
            higher module that imports AppModule in
            app/app.module.ts and QuestionMessageModule in
            pages/question-message/question-message.module.ts.
            You can also create a new NgModule that exports and includes QuestionMessagePage in
            pages/question-message/question-message.ts then
            import that NgModule in AppModule in
            app/app.module.ts and QuestionMessageModule in
            pages/question-message/question-message.module.ts.

SOLUTION: to fix this all i had to do was delete a file called question-message.module.ts

you will also need to remove the @IonicPage decorator from question-message.ts

otherwise you might get an error like this:

[10:37:15]  Error: pages\question-message\question-message.ts
            has a @IonicPage decorator, but it does not have a corresponding "NgModule" at
            pages\question-message\question-message.module.ts
Error: pages\question-message\question-message.ts has a @IonicPage dec
does not have a corresponding "NgModule" at pages\question-message\