What is the short hand for checking the result of this function?

whatwhatwhat 0
Viewed 49

I'm learning Dart and I understand that the below (should be) correct. I now want to understand how to do the shorthand version of this. This function lives in my state container (inherited widget) so that I can call this anywhere in my app. Hopefully calling this function everywhere in my app doesn't count as multiple Firestore queries...

String getUID() {
    final uid = FirebaseAuth.instance.currentUser?.uid.toString();
    if (uid == null || uid == '') {
      return '';
    } else {
      return uid;  
    }    
  }
firebase-authentication dart firebase flutter
3 Answers

You could write it like this:

String getUID() {
    final String? uid = FirebaseAuth.instance.currentUser?.uid.toString();
  
    return uid ?? '';
}

or also as a getter (the getter won't need parentheses to be accessed (), you just call it as if it were an variable .uid):

String get uid => FirebaseAuth.instance.currentUser?.uid ?? '';

The ?? operator will work as:

if(uid == null) {
 return ''; 
}

return uid;

You don't need to check for empty string '' there because you are passing it as empty anyway.

Thiago Fontes0

You can write it like so

String getUID() => FirebaseAuth.instance.currentUser?.uid ?? '';

There is no need for toString() as uid itself is already a String.

Jigar Patel0

how about make on helper.dart

  • helper.dart (or whatever you name it)
import 'the firebase package';
...
String getUID() {
    final uid = FirebaseAuth.instance.currentUser?.uid.toString();
    if (uid == null || uid == '') {
      return '';
    } else {
      return uid;  
    }    
  }

then you can call getUID in every class

  • eg: home.dart
import 'package:../helper.dart';

....
final _uid = getUID();
print(_uid);
....

im not sure this one is best solution, but this what i usually did for common function.

pmatatias0
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