provideEffect

SandroMaglione · Mar 24, 2024 · a3352b5 · a3352b5
1 parent df5740d
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diff --git a/packages/fpdart/lib/src/effect.dart b/packages/fpdart/lib/src/effect.dart
@@ -293,6 +293,16 @@ final class Effect<E, L, R> extends IEffect<E, L, R> {
   /// {@category do_notation}
   Effect<Null, L, R> provide(E env) => Effect._((_) => _unsafeRun(env));
 
+  /// {@category do_notation}
+  Effect<V, L, R> provideEffect<V>(Effect<V, L, E> effect) => Effect._(
+        (env) => effect._unsafeRun(env).then(
+              (exit) => switch (exit) {
+                Left(value: final cause) => Left(cause),
+                Right(value: final value) => _unsafeRun(value),
+              },
+            ),
+      );
+
   /// {@category do_notation}
   static Effect<E, L, E> env<E, L>() => Effect._(
         (env) => Right(env),

diff --git a/packages/fpdart/test/src/effect/effect_do_notation_test.dart b/packages/fpdart/test/src/effect/effect_do_notation_test.dart
@@ -18,6 +18,30 @@ void main() {
         });
       });
 
+      group('provideEffect', () {
+        test('valid dependency', () {
+          final main = Effect<int, String, int>.gen(($) {
+            final env = $.sync(Effect.env());
+            return env + 1;
+          });
+
+          final program = main.provideEffect<Null>(Effect.succeed(10));
+          final result = program.runSyncVoid();
+          expect(result, 11);
+        });
+
+        test('invalid dependency', () {
+          final main = Effect<int, String, int>.gen(($) {
+            final env = $.sync(Effect.env());
+            return env + 1;
+          });
+
+          final program = main.provideEffect<Null>(Effect.fail("error"));
+          final result = program.flip().runSyncVoid();
+          expect(result, "error");
+        });
+      });
+
       group('mapEnv', () {
         test('adapt dependency from another program', () {
           final subMain =