Add async and throwing capability to value closure for Fork (#12)

* Add async and throwing capability to value closure for Fork

* Remove await and prefer parallel await using async let

Author: 0xLeif

Sources/Fork/Fork.swift

@@ -39,7 +39,7 @@ public struct Fork<LeftOutput, RightOutput> {
     ///   - leftOutput: An `async` closure that uses `LeftInput` to return `LeftOutput`
     ///   - rightOutput: An `async` closure that uses `RightInput` to return `RightOutput`
     public init<Value, LeftInput, RightInput>(
-        value: @escaping () -> Value,
+        value: @escaping () async throws -> Value,
         leftInputMap: @escaping (Value) throws -> LeftInput,
         rightInputMap: @escaping (Value) throws -> RightInput,
         leftOutput: @escaping (LeftInput) async throws -> LeftOutput,
@@ -91,7 +91,7 @@ public struct Fork<LeftOutput, RightOutput> {
     ///   - leftOutput: An `async` closure that uses `LeftInput` to return `LeftOutput`
     ///   - rightOutput: An `async` closure that uses `RightInput` to return `RightOutput`
     public init<Value>(
-        value: @escaping () -> Value,
+        value: @escaping () async throws -> Value,
         leftOutput: @escaping (Value) async throws -> LeftOutput,
         rightOutput: @escaping (Value) async throws -> RightOutput
     ) {

Sources/Fork/ForkedArray.swift

@@ -58,14 +58,12 @@ public struct ForkedArray<Value, Output> {
 
     /// Asynchronously resolve the forked array
     public func output() async throws -> [Output] {
-        try await fork.merged(
-            using: { leftForkType, rightForkType in
-                async let leftOutput = try await ForkedArray.output(for: leftForkType, isIncluded: filter, transform: map)
-                async let rightOutput = try await ForkedArray.output(for: rightForkType, isIncluded: filter, transform: map)
-                
-                return try await leftOutput + rightOutput
-            }
-        )
+        try await fork.merged { leftForkType, rightForkType in
+            async let leftOutput = try ForkedArray.output(for: leftForkType, isIncluded: filter, transform: map)
+            async let rightOutput = try ForkedArray.output(for: rightForkType, isIncluded: filter, transform: map)
+            
+            return try await leftOutput + rightOutput
+        }
     }
 }