How to use BLOC pattern to validate 'Confirm Password' text field?

[jonahfang]

I am using a Stream/Observable to validate 'Password' text field like final _emailController = BehaviorSubject(); Stream get email => _emailController.stream.transform(validateEmail); where valdiateEmail is a StreamTransformer<String,String> to validate whether the password length is at least 6. I am trying to use the similar idea for 'Confirm Password' but the validate function would take two inputs: password, confirmPassword; not sure how to handle this using StreamTransformer.

[boeledi]

The easiest way is to use an Observable.combineLatestXXX(), combined with a stream.transform(...).doOnData(...) as follows:

Stream<bool> get registerValid => Observable.combineLatest3(
                                      email, 
                                      password, 
                                      confirmPassword, 
                                      (e, p, c) => (0 == p.compareTo(c))
                                    );

Stream<String> get confirmPassword => 
  _passwordConfirmController.stream.transform(validatePassword)
    .doOnData((String c){
      // If the password is accepted (after validation of the rules)
      // we need to ensure both password and retyped password match
      if (0 != _passwordController.value.compareTo(c)){
        // If they do not match, add an error
        _passwordConfirmController.addError("No Match");
      }
    });

I just wrote an article on BLoC Use cases which contains a full explanation on this topic. The article may be found here

Hope this will help.

[aniltc-rails]

hi I have multiple textfields, in this case how to use combineLatest. let's say I have 10 textfield , its dyanmically created by the user in UI.