Answer

The Answer package simplifies the handling of function returns by allowing them to return either a success or an error object. This enhances code readability and makes error handling more structured.

How to use

To use the package in your Flutter project, simply add the dependency to your pubspec.yaml:

dependencies:
  answer: ^0.0.1

Import the package in your code:

import 'package:answer/answer.dart';

How add Answer return in your code

   Future<Answer<AnswerFailure, String>> getUserId() async {
    try {
        final result = await loginDatasource.getUserId();
        return Answer.success(result);
    } catch (e) {
        return Answer.fail(e);
    }
  }

With extension Answer

    Future<Answer<AnswerFailure, String>> getUserId() async {
        try {
            final result = await loginDatasource.getUserId();
            return result.asAnswer();
        } catch (e) {
            return e.asAnswer();
        }
    }

How handler Answer return in your code

Void function

  Future<void> login() async {
    final answer = await getUserId();
    answer.deal(
      onSuccess: (idUser) {
        print(idUser);
      },
      onError: (error) {
        print(error);
      },
    );
  }

Function with return

  Future<String> login() async {
    final answer = await getUserId();
    return answer.deal(
      onSuccess: (idUser) {
        return idUser;
      },
      onError: (error) {
        return error.message;
      },
    );
  }

Recommended you use AnswerFailure

We recommend that you use the class AnswerFailure as the default response for Failure, this guarantees that your returns will always have a pattern, if you need a specific error, create a new error extending the class Answer Failure

Create your Specific from AnswerFailure

class MyError extends AnswerFailure {
  MyError() : super(
          message: 'MyError',
          code: 1,
        );
}

How add Answer return in your code

Add AnswerFailure as your return in case of errors

   Future<Answer<AnswerFailure, String>> getUserId() async {
    try {
        final result = await loginDatasource.getUserId();
        return Answer.success(result);
    } catch (e) {
        return Answer.fail(MyError());
    }
  }

Handler your custom AnswerFailure

  Future<void> login() async {
    final answer = await getUserId();
    answer.deal(
      onSuccess: (idUser) {
        print(idUser);
      },
      onError: (error) {
        if (error is MyError) {
          print(error.message);
        }else{
          print(error.message);
        }
      },
    );
  }

You also can use AnswerDefault to simplify your code

You can also use TypeDef AnswerDefault simplifying the parameters, it by default returns AnswerFailure and you just need to pass the success object

   Future<AnswerDefault<String>> getUserId() async {
    try {
        final result = await loginDatasource.getUserId();
        return Answer.success(result);
    } catch (e) {
        return Answer.fail(e);
    }
  }

Recommended on tests

Some Mocks libraries for testing contain import name conflicts, in these cases it is recommended that you import the Mocks library with the Hide Answer instruction.

Example

import 'package:answer/answer.dart';
import 'package:mocktail/mocktail.dart' hide Answer;

void main() {
  test('test', () {
      ...
  });
}