diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9632a1e..9a015d1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@ New features:
 Bugfixes:
 
 Other improvements:
+- Use `EffectFn` throughout instead of unsafe `mkEffect` utility (#70 by @colinwahl)
 
 ## [v8.1.0](https://github.com/purescript-node/purescript-node-fs/releases/tag/v8.1.0) - 2022-06-10
 
diff --git a/src/Node/FS/Async.js b/src/Node/FS/Async.js
index 460c3cb..3ddc7a7 100644
--- a/src/Node/FS/Async.js
+++ b/src/Node/FS/Async.js
@@ -23,13 +23,3 @@ export {
   write as writeImpl,
   close as closeImpl
 } from "fs";
-
-export function handleCallbackImpl(left, right, f) {
-  return function (err, value) {
-    if (err) {
-      f(left(err))();
-    } else {
-      f(right(value))();
-    }
-  };
-}
diff --git a/src/Node/FS/Async.purs b/src/Node/FS/Async.purs
index 8060d4a..998bde4 100644
--- a/src/Node/FS/Async.purs
+++ b/src/Node/FS/Async.purs
@@ -39,59 +39,53 @@ import Prelude
 import Data.DateTime (DateTime)
 import Data.DateTime.Instant (fromDateTime, unInstant)
 import Data.Either (Either(..))
-import Data.Function.Uncurried (Fn2, Fn6, Fn4, Fn3, runFn2, runFn6, runFn4, runFn3)
 import Data.Int (round)
 import Data.Maybe (Maybe(..))
-import Data.Nullable (Nullable, toNullable)
+import Data.Nullable (Nullable, toMaybe, toNullable)
 import Data.Time.Duration (Milliseconds(..))
 import Effect (Effect)
 import Effect.Exception (Error)
+import Effect.Uncurried (EffectFn2, EffectFn3, EffectFn4, EffectFn6, mkEffectFn2, runEffectFn2, runEffectFn3, runEffectFn4, runEffectFn6)
 import Node.Buffer (Buffer, size)
 import Node.Encoding (Encoding)
 import Node.FS (FileDescriptor, ByteCount, FilePosition, BufferLength, BufferOffset, FileMode, FileFlags, SymlinkType, fileFlagsToNode, symlinkTypeToNode)
-import Node.FS.Internal (mkEffect)
 import Node.FS.Perms (Perms, permsToString, all, mkPerms)
 import Node.FS.Stats (StatsObj, Stats(..))
 import Node.Path (FilePath)
 
-type JSCallback a = Fn2 (Nullable Error) a Unit
-
-foreign import handleCallbackImpl ::
-  forall a. Fn3 (Error -> Either Error a)
-                (a -> Either Error a)
-                (Callback a)
-                (JSCallback a)
-
-handleCallback :: forall a. (Callback a) -> JSCallback a
-handleCallback cb = runFn3 handleCallbackImpl Left Right cb
+type JSCallback a = EffectFn2 (Nullable Error) a Unit
 
+handleCallback :: forall a. Callback a -> JSCallback a
+handleCallback cb = mkEffectFn2 \err a -> case toMaybe err of
+  Nothing -> cb (Right a)
+  Just err' -> cb (Left err')
 
 -- | Type synonym for callback functions.
 type Callback a = Either Error a -> Effect Unit
 
-foreign import renameImpl :: Fn3 FilePath FilePath (JSCallback Unit) Unit
-foreign import truncateImpl :: Fn3 FilePath Int (JSCallback Unit) Unit
-foreign import chownImpl :: Fn4 FilePath Int Int (JSCallback Unit) Unit
-foreign import chmodImpl :: Fn3 FilePath String (JSCallback Unit) Unit
-foreign import statImpl :: Fn2 FilePath (JSCallback StatsObj) Unit
-foreign import lstatImpl :: Fn2 FilePath (JSCallback StatsObj) Unit
-foreign import linkImpl :: Fn3 FilePath FilePath (JSCallback Unit) Unit
-foreign import symlinkImpl :: Fn4 FilePath FilePath String (JSCallback Unit) Unit
-foreign import readlinkImpl :: Fn2 FilePath (JSCallback FilePath) Unit
-foreign import realpathImpl :: forall cache. Fn3 FilePath { | cache } (JSCallback FilePath) Unit
-foreign import unlinkImpl :: Fn2 FilePath (JSCallback Unit) Unit
-foreign import rmdirImpl :: Fn3 FilePath { maxRetries :: Int, retryDelay :: Int } (JSCallback Unit) Unit
-foreign import rmImpl :: Fn3 FilePath { force :: Boolean, maxRetries :: Int, recursive :: Boolean, retryDelay :: Int } (JSCallback Unit) Unit
-foreign import mkdirImpl :: Fn3 FilePath { recursive :: Boolean, mode :: String } (JSCallback Unit) Unit
-foreign import readdirImpl :: Fn2 FilePath (JSCallback (Array FilePath)) Unit
-foreign import utimesImpl :: Fn4 FilePath Int Int (JSCallback Unit) Unit
-foreign import readFileImpl :: forall a opts. Fn3 FilePath { | opts } (JSCallback a) Unit
-foreign import writeFileImpl :: forall a opts. Fn4 FilePath a { | opts } (JSCallback Unit) Unit
-foreign import appendFileImpl :: forall a opts. Fn4 FilePath a { | opts } (JSCallback Unit) Unit
-foreign import openImpl :: Fn4 FilePath String (Nullable FileMode) (JSCallback FileDescriptor) Unit
-foreign import readImpl :: Fn6 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) (JSCallback ByteCount) Unit
-foreign import writeImpl :: Fn6 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) (JSCallback ByteCount) Unit
-foreign import closeImpl :: Fn2 FileDescriptor (JSCallback Unit) Unit
+foreign import renameImpl :: EffectFn3 FilePath FilePath (JSCallback Unit) Unit
+foreign import truncateImpl :: EffectFn3 FilePath Int (JSCallback Unit) Unit
+foreign import chownImpl :: EffectFn4 FilePath Int Int (JSCallback Unit) Unit
+foreign import chmodImpl :: EffectFn3 FilePath String (JSCallback Unit) Unit
+foreign import statImpl :: EffectFn2 FilePath (JSCallback StatsObj) Unit
+foreign import lstatImpl :: EffectFn2 FilePath (JSCallback StatsObj) Unit
+foreign import linkImpl :: EffectFn3 FilePath FilePath (JSCallback Unit) Unit
+foreign import symlinkImpl :: EffectFn4 FilePath FilePath String (JSCallback Unit) Unit
+foreign import readlinkImpl :: EffectFn2 FilePath (JSCallback FilePath) Unit
+foreign import realpathImpl :: forall cache. EffectFn3 FilePath { | cache } (JSCallback FilePath) Unit
+foreign import unlinkImpl :: EffectFn2 FilePath (JSCallback Unit) Unit
+foreign import rmdirImpl :: EffectFn3 FilePath { maxRetries :: Int, retryDelay :: Int } (JSCallback Unit) Unit
+foreign import rmImpl :: EffectFn3 FilePath { force :: Boolean, maxRetries :: Int, recursive :: Boolean, retryDelay :: Int } (JSCallback Unit) Unit
+foreign import mkdirImpl :: EffectFn3 FilePath { recursive :: Boolean, mode :: String } (JSCallback Unit) Unit
+foreign import readdirImpl :: EffectFn2 FilePath (JSCallback (Array FilePath)) Unit
+foreign import utimesImpl :: EffectFn4 FilePath Int Int (JSCallback Unit) Unit
+foreign import readFileImpl :: forall a opts. EffectFn3 FilePath { | opts } (JSCallback a) Unit
+foreign import writeFileImpl :: forall a opts. EffectFn4 FilePath a { | opts } (JSCallback Unit) Unit
+foreign import appendFileImpl :: forall a opts. EffectFn4 FilePath a { | opts } (JSCallback Unit) Unit
+foreign import openImpl :: EffectFn4 FilePath String (Nullable FileMode) (JSCallback FileDescriptor) Unit
+foreign import readImpl :: EffectFn6 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) (JSCallback ByteCount) Unit
+foreign import writeImpl :: EffectFn6 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) (JSCallback ByteCount) Unit
+foreign import closeImpl :: EffectFn2 FileDescriptor (JSCallback Unit) Unit
 
 
 -- | Renames a file.
@@ -99,7 +93,7 @@ rename :: FilePath
        -> FilePath
        -> Callback Unit
        -> Effect Unit
-rename oldFile newFile cb = mkEffect $ \_ -> runFn3
+rename oldFile newFile cb = runEffectFn3
   renameImpl oldFile newFile (handleCallback cb)
 
 -- | Truncates a file to the specified length.
@@ -108,7 +102,7 @@ truncate :: FilePath
          -> Callback Unit
          -> Effect Unit
 
-truncate file len cb = mkEffect $ \_ -> runFn3
+truncate file len cb = runEffectFn3
   truncateImpl file len (handleCallback cb)
 
 -- | Changes the ownership of a file.
@@ -118,7 +112,7 @@ chown :: FilePath
       -> Callback Unit
       -> Effect Unit
 
-chown file uid gid cb = mkEffect $ \_ -> runFn4
+chown file uid gid cb = runEffectFn4
   chownImpl file uid gid (handleCallback cb)
 
 -- | Changes the permissions of a file.
@@ -127,7 +121,7 @@ chmod :: FilePath
       -> Callback Unit
       -> Effect Unit
 
-chmod file perms cb = mkEffect $ \_ -> runFn3
+chmod file perms cb = runEffectFn3
   chmodImpl file (permsToString perms) (handleCallback cb)
 
 -- | Gets file statistics.
@@ -135,7 +129,7 @@ stat :: FilePath
      -> Callback Stats
      -> Effect Unit
 
-stat file cb = mkEffect $ \_ -> runFn2
+stat file cb = runEffectFn2
   statImpl file (handleCallback $ cb <<< map Stats)
 
 -- | Gets file or symlink statistics. `lstat` is identical to `stat`, except
@@ -144,7 +138,7 @@ stat file cb = mkEffect $ \_ -> runFn2
 lstat :: FilePath
      -> Callback Stats
      -> Effect Unit
-lstat file cb = mkEffect $ \_ -> runFn2
+lstat file cb = runEffectFn2
   lstatImpl file (handleCallback $ cb <<< map Stats)
 
 -- | Creates a link to an existing file.
@@ -153,7 +147,7 @@ link :: FilePath
      -> Callback Unit
      -> Effect Unit
 
-link src dst cb = mkEffect $ \_ -> runFn3
+link src dst cb = runEffectFn3
   linkImpl src dst (handleCallback cb)
 
 -- | Creates a symlink.
@@ -163,7 +157,7 @@ symlink :: FilePath
         -> Callback Unit
         -> Effect Unit
 
-symlink src dest ty cb = mkEffect $ \_ -> runFn4
+symlink src dest ty cb = runEffectFn4
   symlinkImpl src dest (symlinkTypeToNode ty) (handleCallback cb)
 
 -- | Reads the value of a symlink.
@@ -171,7 +165,7 @@ readlink :: FilePath
          -> Callback FilePath
          -> Effect Unit
 
-readlink path cb = mkEffect $ \_ -> runFn2
+readlink path cb = runEffectFn2
   readlinkImpl path (handleCallback cb)
 
 -- | Find the canonicalized absolute location for a path.
@@ -179,7 +173,7 @@ realpath :: FilePath
          -> Callback FilePath
          -> Effect Unit
 
-realpath path cb = mkEffect $ \_ -> runFn3
+realpath path cb = runEffectFn3
   realpathImpl path {} (handleCallback cb)
 
 -- | Find the canonicalized absolute location for a path using a cache object
@@ -189,7 +183,7 @@ realpath' :: forall cache. FilePath
           -> Callback FilePath
           -> Effect Unit
 
-realpath' path cache cb = mkEffect $ \_ -> runFn3
+realpath' path cache cb = runEffectFn3
   realpathImpl path cache (handleCallback cb)
 
 -- | Deletes a file.
@@ -197,7 +191,7 @@ unlink :: FilePath
        -> Callback Unit
        -> Effect Unit
 
-unlink file cb = mkEffect $ \_ -> runFn2
+unlink file cb = runEffectFn2
   unlinkImpl file (handleCallback cb)
 
 -- | Deletes a directory.
@@ -211,7 +205,7 @@ rmdir' :: FilePath
       -> { maxRetries :: Int, retryDelay :: Int }
       -> Callback Unit
       -> Effect Unit
-rmdir' path opts cb = mkEffect $ \_ -> runFn3
+rmdir' path opts cb = runEffectFn3
   rmdirImpl path opts (handleCallback cb)
 
 -- | Deletes a file or directory.
@@ -225,7 +219,7 @@ rm' :: FilePath
       -> { force :: Boolean, maxRetries :: Int, recursive :: Boolean, retryDelay :: Int }
       -> Callback Unit
       -> Effect Unit
-rm' path opts cb = mkEffect $ \_ -> runFn3
+rm' path opts cb = runEffectFn3
   rmImpl path opts (handleCallback cb)
 
 
@@ -241,7 +235,7 @@ mkdir'
   -> { recursive :: Boolean, mode :: Perms }
   -> Callback Unit
   -> Effect Unit
-mkdir' file { recursive, mode: perms } cb = mkEffect $ \_ -> runFn3
+mkdir' file { recursive, mode: perms } cb = runEffectFn3
   mkdirImpl file { recursive, mode: permsToString perms } (handleCallback cb)
 
 -- | Reads the contents of a directory.
@@ -249,7 +243,7 @@ readdir :: FilePath
         -> Callback (Array FilePath)
         -> Effect Unit
 
-readdir file cb = mkEffect $ \_ -> runFn2
+readdir file cb = runEffectFn2
   readdirImpl file (handleCallback cb)
 
 -- | Sets the accessed and modified times for the specified file.
@@ -259,7 +253,7 @@ utimes :: FilePath
        -> Callback Unit
        -> Effect Unit
 
-utimes file atime mtime cb = mkEffect $ \_ -> runFn4
+utimes file atime mtime cb = runEffectFn4
   utimesImpl file
             (fromDate atime)
             (fromDate mtime)
@@ -274,7 +268,7 @@ readFile :: FilePath
          -> Callback Buffer
          -> Effect Unit
 
-readFile file cb = mkEffect $ \_ -> runFn3
+readFile file cb = runEffectFn3
   readFileImpl file {} (handleCallback cb)
 
 -- | Reads the entire contents of a text file with the specified encoding.
@@ -283,7 +277,7 @@ readTextFile ::  Encoding
              -> Callback String
              -> Effect Unit
 
-readTextFile encoding file cb = mkEffect $ \_ -> runFn3
+readTextFile encoding file cb = runEffectFn3
   readFileImpl file { encoding: show encoding } (handleCallback cb)
 
 -- | Writes a buffer to a file.
@@ -292,7 +286,7 @@ writeFile :: FilePath
           -> Callback Unit
           -> Effect Unit
 
-writeFile file buff cb = mkEffect $ \_ -> runFn4
+writeFile file buff cb = runEffectFn4
   writeFileImpl file buff {} (handleCallback cb)
 
 -- | Writes text to a file using the specified encoding.
@@ -302,7 +296,7 @@ writeTextFile ::  Encoding
               -> Callback Unit
               -> Effect Unit
 
-writeTextFile encoding file buff cb = mkEffect $ \_ -> runFn4
+writeTextFile encoding file buff cb = runEffectFn4
   writeFileImpl file buff { encoding: show encoding } (handleCallback cb)
 
 -- | Appends the contents of a buffer to a file.
@@ -311,7 +305,7 @@ appendFile :: FilePath
            -> Callback Unit
            -> Effect Unit
 
-appendFile file buff cb = mkEffect $ \_ -> runFn4
+appendFile file buff cb = runEffectFn4
   appendFileImpl file buff {} (handleCallback cb)
 
 -- | Appends text to a file using the specified encoding.
@@ -321,7 +315,7 @@ appendTextFile ::  Encoding
                -> Callback Unit
                -> Effect Unit
 
-appendTextFile encoding file buff cb = mkEffect $ \_ -> runFn4
+appendTextFile encoding file buff cb = runEffectFn4
   appendFileImpl file buff { encoding: show encoding } (handleCallback cb)
 
 
@@ -332,7 +326,7 @@ fdOpen :: FilePath
        -> Maybe FileMode
        -> Callback FileDescriptor
        -> Effect Unit
-fdOpen file flags mode cb = mkEffect $ \_ -> runFn4 openImpl file (fileFlagsToNode flags) (toNullable mode) (handleCallback cb)
+fdOpen file flags mode cb = runEffectFn4 openImpl file (fileFlagsToNode flags) (toNullable mode) (handleCallback cb)
 
 -- | Read from a file asynchronously. See the [Node Documentation](https://nodejs.org/api/fs.html#fs_fs_read_fd_buffer_offset_length_position_callback)
 -- | for details.
@@ -343,7 +337,7 @@ fdRead :: FileDescriptor
        -> Maybe FilePosition
        -> Callback ByteCount
        -> Effect Unit
-fdRead fd buff off len pos cb =  mkEffect $ \_ -> runFn6 readImpl fd buff off len (toNullable pos) (handleCallback cb)
+fdRead fd buff off len pos cb = runEffectFn6 readImpl fd buff off len (toNullable pos) (handleCallback cb)
 
 -- | Convenience function to fill the whole buffer from the current
 -- | file position.
@@ -364,7 +358,7 @@ fdWrite :: FileDescriptor
         -> Maybe FilePosition
         -> Callback ByteCount
         -> Effect Unit
-fdWrite fd buff off len pos cb = mkEffect $ \_ -> runFn6 writeImpl fd buff off len (toNullable pos) (handleCallback cb)
+fdWrite fd buff off len pos cb = runEffectFn6 writeImpl fd buff off len (toNullable pos) (handleCallback cb)
 
 -- | Convenience function to append the whole buffer to the current
 -- | file position.
@@ -381,4 +375,4 @@ fdAppend fd buff cb = do
 fdClose :: FileDescriptor
         -> Callback Unit
         -> Effect Unit
-fdClose fd cb = mkEffect $ \_ -> runFn2 closeImpl fd (handleCallback cb)
+fdClose fd cb = runEffectFn2 closeImpl fd (handleCallback cb)
diff --git a/src/Node/FS/Internal.purs b/src/Node/FS/Internal.purs
deleted file mode 100644
index ea21e6b..0000000
--- a/src/Node/FS/Internal.purs
+++ /dev/null
@@ -1,10 +0,0 @@
-
-module Node.FS.Internal where
-
-import Prelude
-
-import Effect (Effect)
-import Unsafe.Coerce (unsafeCoerce)
-
-mkEffect :: forall a. (Unit -> a) -> Effect a
-mkEffect = unsafeCoerce
diff --git a/src/Node/FS/Stream.purs b/src/Node/FS/Stream.purs
index 2c503a0..f795445 100644
--- a/src/Node/FS/Stream.purs
+++ b/src/Node/FS/Stream.purs
@@ -14,20 +14,19 @@ module Node.FS.Stream
   ) where
 
 import Prelude
+
 import Data.Maybe (Maybe(..))
-import Data.Function.Uncurried (Fn2, runFn2)
 import Data.Nullable (Nullable, toNullable)
 import Effect (Effect)
-import Node.Stream (Readable(), Writable())
-import Node.Path (FilePath())
-
+import Effect.Uncurried (EffectFn2, runEffectFn2)
 import Node.FS (FileDescriptor, FileFlags(..), fileFlagsToNode)
-import Node.FS.Perms (Perms())
+import Node.FS.Perms (Perms)
 import Node.FS.Perms as Perms
-import Node.FS.Internal (mkEffect)
+import Node.Path (FilePath)
+import Node.Stream (Readable, Writable)
 
-foreign import createReadStreamImpl  :: forall opts. Fn2 (Nullable FilePath) { | opts } (Readable ())
-foreign import createWriteStreamImpl :: forall opts. Fn2 (Nullable FilePath) { | opts } (Writable ())
+foreign import createReadStreamImpl  :: forall opts. EffectFn2 (Nullable FilePath) { | opts } (Readable ())
+foreign import createWriteStreamImpl :: forall opts. EffectFn2 (Nullable FilePath) { | opts } (Writable ())
 
 readWrite :: Perms
 readWrite = Perms.mkPerms rw rw rw
@@ -67,7 +66,7 @@ defaultWriteStreamOptions =
 createWriteStreamWith :: WriteStreamOptions
                       -> FilePath
                       -> Effect (Writable ())
-createWriteStreamWith opts file = mkEffect $ \_ -> runFn2
+createWriteStreamWith opts file = runEffectFn2
   createWriteStreamImpl (nonnull file)
     { mode: Perms.permsToInt opts.perms
     , flags: fileFlagsToNode opts.flags
@@ -77,7 +76,7 @@ createWriteStreamWith opts file = mkEffect $ \_ -> runFn2
 fdCreateWriteStreamWith :: WriteStreamOptions
                         -> FileDescriptor
                         -> Effect (Writable ())
-fdCreateWriteStreamWith opts fd = mkEffect $ \_ -> runFn2
+fdCreateWriteStreamWith opts fd = runEffectFn2
   createWriteStreamImpl null
     { fd
     , mode: Perms.permsToInt opts.perms
@@ -113,7 +112,7 @@ defaultReadStreamOptions =
 createReadStreamWith :: ReadStreamOptions
                      -> FilePath
                      -> Effect (Readable ())
-createReadStreamWith opts file = mkEffect $ \_ -> runFn2
+createReadStreamWith opts file = runEffectFn2
   createReadStreamImpl (nonnull file)
     { mode: Perms.permsToInt opts.perms
     , flags: fileFlagsToNode opts.flags
@@ -124,7 +123,7 @@ createReadStreamWith opts file = mkEffect $ \_ -> runFn2
 fdCreateReadStreamWith :: ReadStreamOptions
                        -> FileDescriptor
                        -> Effect (Readable ())
-fdCreateReadStreamWith opts fd = mkEffect $ \_ -> runFn2
+fdCreateReadStreamWith opts fd = runEffectFn2
   createReadStreamImpl null
     { fd
     , mode: Perms.permsToInt opts.perms
diff --git a/src/Node/FS/Sync.purs b/src/Node/FS/Sync.purs
index 7594495..c89c2ec 100644
--- a/src/Node/FS/Sync.purs
+++ b/src/Node/FS/Sync.purs
@@ -40,11 +40,10 @@ import Effect (Effect)
 import Data.DateTime (DateTime)
 import Data.Time.Duration (Milliseconds(..))
 import Data.DateTime.Instant (fromDateTime, unInstant)
-import Data.Function.Uncurried (Fn1, Fn5, Fn3, Fn2,
-                                runFn1, runFn5, runFn3, runFn2)
 import Data.Nullable (Nullable(), toNullable)
 import Data.Int (round)
 import Data.Maybe (Maybe(..))
+import Effect.Uncurried (EffectFn1, EffectFn2, EffectFn3, EffectFn5, runEffectFn1, runEffectFn2, runEffectFn3, runEffectFn5)
 import Node.Buffer (Buffer(), size)
 import Node.Encoding (Encoding)
 
@@ -54,40 +53,39 @@ import Node.FS (FileDescriptor, ByteCount, FilePosition, BufferLength,
 import Node.FS.Stats (StatsObj, Stats(..))
 import Node.Path (FilePath())
 import Node.FS.Perms (Perms, permsToString, all, mkPerms)
-import Node.FS.Internal (mkEffect)
-
-foreign import renameSyncImpl :: Fn2 FilePath FilePath Unit
-foreign import truncateSyncImpl :: Fn2 FilePath Int Unit
-foreign import chownSyncImpl :: Fn3 FilePath Int Int Unit
-foreign import chmodSyncImpl :: Fn2 FilePath String Unit
-foreign import statSyncImpl :: Fn1 FilePath StatsObj
-foreign import lstatSyncImpl :: Fn1 FilePath StatsObj
-foreign import linkSyncImpl :: Fn2 FilePath FilePath Unit
-foreign import symlinkSyncImpl :: Fn3 FilePath FilePath String Unit
-foreign import readlinkSyncImpl :: Fn1 FilePath FilePath
-foreign import realpathSyncImpl :: forall cache. Fn2 FilePath { | cache } FilePath
-foreign import unlinkSyncImpl :: Fn1 FilePath Unit
-foreign import rmdirSyncImpl :: Fn2 FilePath { maxRetries :: Int, retryDelay :: Int } Unit
-foreign import rmSyncImpl :: Fn2 FilePath { force :: Boolean, maxRetries :: Int, recursive :: Boolean, retryDelay :: Int } Unit
-foreign import mkdirSyncImpl :: Fn2 FilePath { recursive :: Boolean, mode :: String } Unit
-foreign import readdirSyncImpl :: Fn1 FilePath (Array FilePath)
-foreign import utimesSyncImpl :: Fn3 FilePath Int Int Unit
-foreign import readFileSyncImpl :: forall a opts. Fn2 FilePath { | opts } a
-foreign import writeFileSyncImpl :: forall a opts. Fn3 FilePath a { | opts } Unit
-foreign import appendFileSyncImpl :: forall a opts. Fn3 FilePath a { | opts } Unit
-foreign import existsSyncImpl :: FilePath -> Boolean
-foreign import openSyncImpl :: Fn3 FilePath String (Nullable FileMode) FileDescriptor
-foreign import readSyncImpl :: Fn5 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) ByteCount
-foreign import writeSyncImpl :: Fn5 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) ByteCount
-foreign import fsyncSyncImpl :: Fn1 FileDescriptor Unit
-foreign import closeSyncImpl :: Fn1 FileDescriptor Unit
+
+foreign import renameSyncImpl :: EffectFn2 FilePath FilePath Unit
+foreign import truncateSyncImpl :: EffectFn2 FilePath Int Unit
+foreign import chownSyncImpl :: EffectFn3 FilePath Int Int Unit
+foreign import chmodSyncImpl :: EffectFn2 FilePath String Unit
+foreign import statSyncImpl :: EffectFn1 FilePath StatsObj
+foreign import lstatSyncImpl :: EffectFn1 FilePath StatsObj
+foreign import linkSyncImpl :: EffectFn2 FilePath FilePath Unit
+foreign import symlinkSyncImpl :: EffectFn3 FilePath FilePath String Unit
+foreign import readlinkSyncImpl :: EffectFn1 FilePath FilePath
+foreign import realpathSyncImpl :: forall cache. EffectFn2 FilePath { | cache } FilePath
+foreign import unlinkSyncImpl :: EffectFn1 FilePath Unit
+foreign import rmdirSyncImpl :: EffectFn2 FilePath { maxRetries :: Int, retryDelay :: Int } Unit
+foreign import rmSyncImpl :: EffectFn2 FilePath { force :: Boolean, maxRetries :: Int, recursive :: Boolean, retryDelay :: Int } Unit
+foreign import mkdirSyncImpl :: EffectFn2 FilePath { recursive :: Boolean, mode :: String } Unit
+foreign import readdirSyncImpl :: EffectFn1 FilePath (Array FilePath)
+foreign import utimesSyncImpl :: EffectFn3 FilePath Int Int Unit
+foreign import readFileSyncImpl :: forall a opts. EffectFn2 FilePath { | opts } a
+foreign import writeFileSyncImpl :: forall a opts. EffectFn3 FilePath a { | opts } Unit
+foreign import appendFileSyncImpl :: forall a opts. EffectFn3 FilePath a { | opts } Unit
+foreign import existsSyncImpl :: EffectFn1 FilePath Boolean
+foreign import openSyncImpl :: EffectFn3 FilePath String (Nullable FileMode) FileDescriptor
+foreign import readSyncImpl :: EffectFn5 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) ByteCount
+foreign import writeSyncImpl :: EffectFn5 FileDescriptor Buffer BufferOffset BufferLength (Nullable FilePosition) ByteCount
+foreign import fsyncSyncImpl :: EffectFn1 FileDescriptor Unit
+foreign import closeSyncImpl :: EffectFn1 FileDescriptor Unit
 
 -- | Renames a file.
 rename :: FilePath
        -> FilePath
        -> Effect Unit
 
-rename oldFile newFile = mkEffect $ \_ -> runFn2
+rename oldFile newFile = runEffectFn2
   renameSyncImpl oldFile newFile
 
 -- | Truncates a file to the specified length.
@@ -95,7 +93,7 @@ truncate :: FilePath
          -> Int
          -> Effect Unit
 
-truncate file len = mkEffect $ \_ -> runFn2
+truncate file len = runEffectFn2
   truncateSyncImpl file len
 
 -- | Changes the ownership of a file.
@@ -104,7 +102,7 @@ chown :: FilePath
       -> Int
       -> Effect Unit
 
-chown file uid gid = mkEffect $ \_ -> runFn3
+chown file uid gid = runEffectFn3
   chownSyncImpl file uid gid
 
 -- | Changes the permissions of a file.
@@ -112,14 +110,14 @@ chmod :: FilePath
       -> Perms
       -> Effect Unit
 
-chmod file perms = mkEffect $ \_ -> runFn2
+chmod file perms = runEffectFn2
   chmodSyncImpl file (permsToString perms)
 
 -- | Gets file statistics.
 stat :: FilePath
      -> Effect Stats
 
-stat file = map Stats $ mkEffect $ \_ -> runFn1
+stat file = map Stats $ runEffectFn1
   statSyncImpl file
 
 -- | Gets file or symlink statistics. `lstat` is identical to `stat`, except
@@ -128,7 +126,7 @@ stat file = map Stats $ mkEffect $ \_ -> runFn1
 lstat :: FilePath
      -> Effect Stats
 
-lstat file = map Stats $ mkEffect $ \_ -> runFn1
+lstat file = map Stats $ runEffectFn1
   lstatSyncImpl file
 
 -- | Creates a link to an existing file.
@@ -136,7 +134,7 @@ link :: FilePath
      -> FilePath
      -> Effect Unit
 
-link src dst = mkEffect $ \_ -> runFn2
+link src dst = runEffectFn2
   linkSyncImpl src dst
 
 -- | Creates a symlink.
@@ -145,21 +143,21 @@ symlink :: FilePath
         -> SymlinkType
         -> Effect Unit
 
-symlink src dst ty = mkEffect $ \_ -> runFn3
+symlink src dst ty = runEffectFn3
   symlinkSyncImpl src dst (symlinkTypeToNode ty)
 
 -- | Reads the value of a symlink.
 readlink :: FilePath
          -> Effect FilePath
 
-readlink path = mkEffect $ \_ -> runFn1
+readlink path = runEffectFn1
   readlinkSyncImpl path
 
 -- | Find the canonicalized absolute location for a path.
 realpath :: FilePath
          -> Effect FilePath
 
-realpath path = mkEffect $ \_ -> runFn2
+realpath path = runEffectFn2
   realpathSyncImpl path {}
 
 -- | Find the canonicalized absolute location for a path using a cache object for
@@ -168,14 +166,14 @@ realpath' :: forall  cache. FilePath
                             -> { | cache }
                             -> Effect FilePath
 
-realpath' path cache = mkEffect $ \_ -> runFn2
+realpath' path cache = runEffectFn2
   realpathSyncImpl path cache
 
 -- | Deletes a file.
 unlink :: FilePath
        -> Effect Unit
 
-unlink file = mkEffect $ \_ -> runFn1
+unlink file = runEffectFn1
   unlinkSyncImpl file
 
 -- | Deletes a directory.
@@ -187,7 +185,7 @@ rmdir path = rmdir' path { maxRetries: 0, retryDelay: 100 }
 rmdir' :: FilePath
       -> { maxRetries :: Int, retryDelay :: Int }
       -> Effect Unit
-rmdir' path opts = mkEffect $ \_ -> runFn2
+rmdir' path opts = runEffectFn2
   rmdirSyncImpl path opts
 
 -- | Deletes a file or directory.
@@ -199,7 +197,7 @@ rm path = rm' path { force: false, maxRetries: 100, recursive: false, retryDelay
 rm' :: FilePath
       -> { force :: Boolean, maxRetries :: Int, recursive :: Boolean, retryDelay :: Int }
       -> Effect Unit
-rm' path opts = mkEffect $ \_ -> runFn2
+rm' path opts = runEffectFn2
   rmSyncImpl path opts
 
 
@@ -213,14 +211,14 @@ mkdir'
   :: FilePath
   -> { recursive :: Boolean, mode :: Perms }
   -> Effect Unit
-mkdir' file { recursive, mode: perms } = mkEffect $ \_ -> runFn2
+mkdir' file { recursive, mode: perms } = runEffectFn2
   mkdirSyncImpl file { recursive, mode: permsToString perms }
 
 -- | Reads the contents of a directory.
 readdir :: FilePath
         -> Effect (Array FilePath)
 
-readdir file = mkEffect $ \_ -> runFn1
+readdir file = runEffectFn1
   readdirSyncImpl file
 
 -- | Sets the accessed and modified times for the specified file.
@@ -229,7 +227,7 @@ utimes :: FilePath
        -> DateTime
        -> Effect Unit
 
-utimes file atime mtime = mkEffect $ \_ -> runFn3
+utimes file atime mtime = runEffectFn3
   utimesSyncImpl file
                 (fromDate atime)
                 (fromDate mtime)
@@ -242,7 +240,7 @@ utimes file atime mtime = mkEffect $ \_ -> runFn3
 readFile :: FilePath
          -> Effect Buffer
 
-readFile file = mkEffect $ \_ -> runFn2
+readFile file = runEffectFn2
   readFileSyncImpl file {}
 
 -- | Reads the entire contents of a text file with the specified encoding.
@@ -250,7 +248,7 @@ readTextFile :: Encoding
              -> FilePath
              -> Effect String
 
-readTextFile encoding file = mkEffect $ \_ -> runFn2
+readTextFile encoding file = runEffectFn2
   readFileSyncImpl file { encoding: show encoding }
 
 -- | Writes a buffer to a file.
@@ -258,7 +256,7 @@ writeFile :: FilePath
           -> Buffer
           -> Effect Unit
 
-writeFile file buff = mkEffect $ \_ -> runFn3
+writeFile file buff = runEffectFn3
   writeFileSyncImpl file buff {}
 
 -- | Writes text to a file using the specified encoding.
@@ -267,7 +265,7 @@ writeTextFile :: Encoding
               -> String
               -> Effect Unit
 
-writeTextFile encoding file text = mkEffect $ \_ -> runFn3
+writeTextFile encoding file text = runEffectFn3
   writeFileSyncImpl file text { encoding: show encoding }
 
 -- | Appends the contents of a buffer to a file.
@@ -275,7 +273,7 @@ appendFile :: FilePath
            -> Buffer
            -> Effect Unit
 
-appendFile file buff = mkEffect $ \_ -> runFn3
+appendFile file buff = runEffectFn3
   appendFileSyncImpl file buff {}
 
 -- | Appends text to a file using the specified encoding.
@@ -284,13 +282,13 @@ appendTextFile :: Encoding
                -> String
                -> Effect Unit
 
-appendTextFile encoding file buff = mkEffect $ \_ -> runFn3
+appendTextFile encoding file buff = runEffectFn3
   appendFileSyncImpl file buff { encoding: show encoding }
 
 -- | Check if the path exists.
 exists :: FilePath
        -> Effect Boolean
-exists file = mkEffect $ \_ -> existsSyncImpl file
+exists file = runEffectFn1 existsSyncImpl file
 
 -- | Open a file synchronously. See the [Node documentation](http://nodejs.org/api/fs.html#fs_fs_opensync_path_flags_mode)
 -- | for details.
@@ -298,8 +296,8 @@ fdOpen :: FilePath
        -> FileFlags
        -> Maybe FileMode
        -> Effect FileDescriptor
-fdOpen file flags mode = mkEffect $ \_ ->
-  runFn3 openSyncImpl file (fileFlagsToNode flags) (toNullable mode)
+fdOpen file flags mode = runEffectFn3
+  openSyncImpl file (fileFlagsToNode flags) (toNullable mode)
 
 -- | Read from a file synchronously. See the [Node documentation](http://nodejs.org/api/fs.html#fs_fs_readsync_fd_buffer_offset_length_position)
 -- | for details.
@@ -310,7 +308,7 @@ fdRead :: FileDescriptor
        -> Maybe FilePosition
        -> Effect ByteCount
 fdRead fd buff off len pos =
-  mkEffect $ \_ -> runFn5 readSyncImpl fd buff off len (toNullable pos)
+  runEffectFn5 readSyncImpl fd buff off len (toNullable pos)
 
 -- | Convenience function to fill the whole buffer from the current
 -- | file position.
@@ -330,7 +328,7 @@ fdWrite :: FileDescriptor
         -> Maybe FilePosition
         -> Effect ByteCount
 fdWrite fd buff off len pos =
-  mkEffect $ \_ -> runFn5 writeSyncImpl fd buff off len (toNullable pos)
+  runEffectFn5 writeSyncImpl fd buff off len (toNullable pos)
 
 -- | Convenience function to append the whole buffer to the current
 -- | file position.
@@ -345,10 +343,10 @@ fdAppend fd buff = do
 -- | for details.
 fdFlush :: FileDescriptor
         -> Effect Unit
-fdFlush fd = mkEffect $ \_ -> runFn1 fsyncSyncImpl fd
+fdFlush fd = runEffectFn1 fsyncSyncImpl fd
 
 -- | Close a file synchronously. See the [Node documentation](http://nodejs.org/api/fs.html#fs_fs_closesync_fd)
 -- | for details.
 fdClose :: FileDescriptor
         -> Effect Unit
-fdClose fd = mkEffect $ \_ -> runFn1 closeSyncImpl fd
+fdClose fd = runEffectFn1 closeSyncImpl fd