RAC vs The Standard Implementations

RAC_Comparison_Examples.m

///////
//signal
///////

//conventional
- (BOOL)isFormValid {
    return [self.usernameField.text length] > 0 &&
            [self.emailField.text length] > 0 &&
            [self.passwordField.text length] > 0 &&
            [self.passwordField.text isEqual:self.passwordVerificationField.text];
}

#pragma mark - UITextFieldDelegate

- (BOOL)textField:(UITextField *)textField
shouldChangeCharactersInRange:(NSRange)range
replacementString:(NSString *)string
{
    self.createButton.enabled = [self isFormValid];

    return YES;
}


//RAC
RACSignal *formValid = [RACSignal
  combineLatest:@[
    self.username.rac_textSignal,
    self.emailField.rac_textSignal,
    self.passwordField.rac_textSignal,
    self.passwordVerificationField.rac_textSignal
  ]
  reduce:^(NSString *username, NSString *email, NSString *password, NSString *passwordVerification) {
    return @([username length] > 0 && [email length] > 0 && [password length] > 8 && [password isEqual:passwordVerification]);
  }];

RAC(self.createButton.enabled) = formValid;


/////Sequence//////

RACSequence *normalizedLongWords = [[words.rac_sequence
    filter:^ BOOL (NSString *word) {
        return [word length] >= 10;
    }]
    map:^(NSString *word) {
        return [word lowercaseString];
    }];