open_meteo_api

Open Meteo API - fpdart

This is a re-implementation using fpdart and functional programming of the Open Meteo API from the flutter_weather app example in the bloc package.

The goal is to show a comparison between usual dart code and functional code written using fpdart.

Structure

The example is simple but comprehensive.

The Open Meteo API implementation is only 1 file. The original source is open_meteo_api_client.dart (copy of the bloc package implementation).

Inside lib/src/fpdart you can then find the refactoring using functional programming and fpdart:

• open_meteo_api_client_fpdart.dart: implementation of the Open Meteo API with fpdart
• location_failure.dart: failure classes for the locationSearch request
• weather_failure.dart: failure classes for the getWeather request

Test

Also the test has been rewritten based on the fpdart refactoring:

• open_meteo_api_client_test.dart: Original Open Meteo API test implementation
• open_meteo_api_client_test_fpdart.dart: Testing for the new implementation using fpdart and functional programming

Types used from fpdart

• TaskEither: Used instead of Future to make async request that may fail
• Either: Used to validate the response from the API with either an error or a valid value
• Option: Used to get values that may be missing
  • lookup in a Map: getting a value by key in a Map may return nothing if the key is not found
  • head in a List: The list may be empty, so getting the first element (called "head") may return nothing