Add mapError

jamil7 · Nov 30, 2020 · dd3ed50 · dd3ed50
1 parent cfaefd3
commit dd3ed50
Showing 1 changed file with 4 additions and 0 deletions.
diff --git a/src/AsyncResult.fs b/src/AsyncResult.fs
@@ -27,6 +27,7 @@ module AsyncResultOperators =
 
 namespace FSharp.Prelude
 
+open FSharp.Prelude
 open FSharp.Prelude.Operators.AsyncResult
 open System.Threading.Tasks
 
@@ -45,6 +46,9 @@ module AsyncResult =
 
     let bind (f: 'a -> AsyncResult<'b, 'e>) (asyncResult: AsyncResult<'a, 'e>): AsyncResult<'b, 'e> = f >>= asyncResult
 
+    let mapError (f: 'e1 -> 'e2) (asyncResult: AsyncResult<'a, 'e1>): AsyncResult<'a, 'e2> =
+        Async.map (Result.mapError f) asyncResult
+
     let bindError (f: 'e1 -> AsyncResult<'a, 'e2>) (asyncResult: AsyncResult<'a, 'e1>): AsyncResult<'a, 'e2> =
         Async.bind (function
             | Ok ok -> singleton ok