Illegal conversion from List<String> to List<Beverage__c>

Question

I have trouble with a component in an Experience site. I'm doing a search bar, which makes a search in the information of two components. It has to show the coincidence or a message like "there's no a coincide". I put the coincidence found in a list so, I'm trying to make a conditional with if but I have an error.

@AuraEnabled
    public static List<Beverage__c> showMessage (String searchKey) {
        String name = '%' + searchKey + '%';
        List <Beverage__c> findCoffee = [SELECT Id, Name, Status__c FROM Beverage__c WHERE Name LIKE :Name AND Type__c = 'Hot'];
        List <String> msg = new List <String> {'We do not have this coffee'};
        if(findCoffee.isEmpty()) {
            return msg;
        } else {
            return findCoffee;
        }
    }

And the error says: Illegal conversion from List to List<Beverage__c>

I hope somebody could help me. Thank you :D

I've tried...

public class Result  {
        @AuraEnabled public List<Beverage__c> beverages { get; set;}
        @AuraEnabled public String message { get; set;}
        public Result(){
        beverages = new List<Beverage__c>();
        message = '';
        }
    } 
    
    @AuraEnabled
    public static List<Beverage__c> showMessage (String searchKey) {
        String name = '%' + searchKey + '%';
        List <Beverage__c> findCoffee = [SELECT Id, Name, Status__c FROM Beverage__c WHERE Name LIKE :Name AND Type__c = 'Hot'];
        Result r = new Result();
        if(findCoffee.isEmpty()) {
            r.message = 'We do not have this coffee';
        } else {
            r.beverages = findCoffee;
        }
        return r;
    }
}

And I got the error Illegal conversion from HotCoffeeListController.Result to List<Beverage__c>

Answer 1

Because Apex is strongly typed, you have to return the type of object that your method specifies - in this case a List<Beverage__c>

You can either return an empty beverage list ie:

return new List<Beverage__c>();

Or create a return object that contains the list and an error message.

Declare your inner class (can be inside the main class you have above):

public class Result  {
  @AuraEnabled public List<Beverage__c> beverages { get; set; }
  @AuraEnabled public String message { get; set; }
  public Result(){
    beverages = new List<Beverage__c>();
    message = '';
  }
} 

Then you code in showMessage would have this at the end:

Result r = new Result();

if (findCoffee.isEmpty()){
  r.message = 'We do not have this coffee';
}
else {
  r.beverages = findCoffee;
}
return r;