[Question] is there any better way to combine two Reader<Deps1, Result1> and Reader<Deps2, Result2>? about fpdart

[SandroMaglione]

Hi @apiep

Am I correct in assuming that you just want to execute task1 and task2 one after the other, without dependencies between the two?

In that case you can use local to change the context from Deps1 to Deps2:

import 'package:fpdart/fpdart.dart';

class Deps1 {
  final String dep;
  const Deps1(this.dep);
}

class Deps2 {
  final String dep;
  const Deps2(this.dep);
}

Reader<Deps1, Task<bool>> waitForAuthenticated() => Reader(
      (deps1) {
        print('Execute waitForAuthenticated: ${deps1.dep}');
        return Task.of(true);
      },
    );

Reader<Deps2, Task<String>> getSomething() => Reader(
      (deps2) {
        print('Execute getSomething: ${deps2.dep}');
        return Task.of("");
      },
    );

void main() async {
  const _deps1 = Deps1('I am Deps1');
  const _deps2 = Deps2('I am Deps2');
  final pipe = waitForAuthenticated()
      .local<Deps2>(constF(_deps1))
      .andThen(getSomething)
      .run(_deps2);

  final result = await pipe.run();
}

This code chains the calls to waitForAuthenticated and getSomething by calling them one after the other. The result is the following:

Execute waitForAuthenticated: I am Deps1
Execute getSomething: I am Deps2

Is this what you where looking for?

[apiep]

Yes it is something like that, that I wanted. Thank you :)

I noticed local method before, but because it has a parameter with it, that's the part what confuse me