AsyncSeq.toArray, toList

Author: eulerfx

src/FSharpx.Async/AsyncSeq.fs

@@ -477,6 +477,17 @@ module AsyncSeq =
       | Nil -> return Nil 
     else return! input }
 
+  /// Creates an async computation which iterates the AsyncSeq and collects the output into an array.
+  let toArray (input:AsyncSeq<'T>) : Async<'T[]> =
+    input
+    |> fold (fun (arr:ResizeArray<_>) a -> arr.Add(a) ; arr) (new ResizeArray<_>()) 
+    |> Async.map (fun arr -> arr.ToArray())
+
+  /// Creates an async computation which iterates the AsyncSeq and collects the output into a list.
+  let toList (input:AsyncSeq<'T>) : Async<'T list> =
+    input |> fold (fun arr a -> a::arr) []
+
+
 [<AutoOpen>]
 module AsyncSeqExtensions = 
   /// Builds an asynchronou sequence using the computation builder syntax

tests/FSharpx.Async.Tests/AsyncSeqTests.fs

@@ -13,3 +13,33 @@ let ``skipping should return all elements after the first non-match``() =
         |> AsyncSeq.toBlockingSeq 
         |> Seq.toList
     Assert.AreEqual(expected, result)
+
+
+[<Test>]
+let ``toArray should collect the results into an array``() =
+  
+  let s = asyncSeq {
+    yield 1
+    yield 2
+    yield 3
+  }
+
+  let a = s |> AsyncSeq.toArray |> Async.RunSynchronously |> Array.toList
+
+  Assert.True(([1;2;3] = a))
+
+[<Test>]
+let ``toList should collect the results into an array``() =
+  
+  let s = asyncSeq {
+    yield 1
+    yield 2
+    yield 3
+  }
+
+  let a = s |> AsyncSeq.toList |> Async.RunSynchronously
+
+  Assert.True(([1;2;3] = a))
+
+    
+