Introduction

Data Channel for Dart and Flutter.

data_channel (DC) is a simple dart utility for handling exceptions and data routing. It is not a very ideal solution to handle exceptions using try and catch at every function, use data_channel instead. data_channel will take care of the routing of errors and data.

Installation

Go to https://pub.dev/packages/data_channel#-installing-tab- for the latest version of data_channel

Example

Return data from getStarwarsCharacters method

import 'package:data_channel/data_channel.dart';

Future<DC<Exception, StarwarsResponse>> getStarwarsCharacters() async {
    try {
	  final _response = await http.get('https://starwars-api.com/characters');
	  
      if (_response.body != null) {
        _starWarsData = StarwarsResponse.fromJson(
            json.decode(_response.body) as Map<String, dynamic>);
      } else {
        _exception = Exception('No data available');
      }

      if (_exception != null) {
        return DC.error(
          _exception,
        );
      }

      return DC.data(
        _starWarsData,
      );
    } on Exception {
      return DC.error(
       	Exception('Some error occured'),
      );
    }
 }

Check for errors

void getStarwarsCharacters() async {
    final _starWarsData = await getStarwarsCharacters();

    if (_starWarsData.hasError) {
      // do something
    } else if (_starWarsData.hasData) {
      // do something
    }
 }

DC forward

forward will help to avoid redundant error checks. We can easily forward a different data model to the callee instead of the original incoming data model. DC.forward will forward the error, if present, else data will be returned.

Future<DC<Exception, UserModel>> checkSomethingAndReturn() {
      final _starWarsData = await getStarwarsCharacters();

    return DC.forward(
      loginData,
      UserModel(id: _starWarsData.id),
    );
  }

DC pick

Cherry pick values using DC.pick

• onError will return error, if present
• onNoError will return data if error is not present
• onData will return data if data is available
• onNoData will return if data is not available

  final appData = await getSomeLoginData();
  appData.pick(
    onError: (error) {
      if (error is CacheException) {
        alerts.setException(context, error);
      }
    },
    onData: (data) {
      value1 = data;
    },
    onNoData: () {
      value1 = getDefaultValue();
    },
  );

  // or

  appData.pick(
    onError: (error) {
      if (error is CacheException) {
        alerts.setException(context, error);
      }
    },
    onNoError: (data) {
      if (data != null) {
        value1 = data;

        return;
      }

      value1 = getDefaultValue();
    },
  );

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Contacts

Please feel free to contact me at ganeshrvel@outlook.com

About

• Author: Ganesh Rathinavel
• License: MIT
• Package URL: https://pub.dev/packages/data_channel
• Repo URL: https://github.com/ganeshrvel/pub-data-channel
• Contacts: ganeshrvel@outlook.com

License

data_channel | Data Channel for Dart and Flutter. MIT License.

Copyright © 2018-Present Ganesh Rathinavel