fix: timeslice shenanigans

src/Node.Stream.CSV.Parse.purs

@@ -3,6 +3,7 @@ module Node.Stream.CSV.Parse where
 import Prelude hiding (join)
 
 import Control.Alt ((<|>))
+import Control.Alternative (guard)
 import Control.Monad.Error.Class (liftEither)
 import Control.Monad.Except (runExcept)
 import Control.Monad.Maybe.Trans (MaybeT(..), runMaybeT)
@@ -20,12 +21,13 @@ import Data.Filterable (filter)
 import Data.Map (Map)
 import Data.Map as Map
 import Data.Maybe (Maybe(..), isNothing)
+import Data.Newtype (wrap)
 import Data.Nullable (Nullable)
 import Data.Nullable as Nullable
 import Data.Traversable (for)
 import Effect (Effect)
 import Effect as Effect
-import Effect.Aff (Canceler(..), makeAff)
+import Effect.Aff (Canceler(..), delay, makeAff)
 import Effect.Aff.Class (class MonadAff, liftAff)
 import Effect.Class (liftEffect)
 import Effect.Exception (error)
@@ -120,7 +122,14 @@ foreach
   => CSVParser r x
   -> ({ | r } -> m Unit)
   -> m Unit
-foreach stream cb = whileJust do
+foreach stream cb =
+  whileJust
+  $ runMaybeT
+  $ do
+      liftAff $ delay $ wrap 0.0
+
+      guard =<< not <$> liftEffect (Stream.closed stream)
+
       isReadable <- liftEffect $ Stream.readable stream
       liftAff $ when (not isReadable) $ makeAff \res -> do
         stop <- flip (Event.once Stream.readableH) stream $ res $ Right unit
@@ -133,9 +142,9 @@ foreach stream cb = whileJust do
         pure $ isNothing r
       records <- liftEffect $ ST.toEffect $ Array.ST.unsafeFreeze recordsST
 
-  parTraverse_ cb records
-  isClosed <- liftEffect $ Stream.closed stream
-  pure $ if isClosed then Nothing else Just unit
+      lift $ parTraverse_ cb records
+      guard =<< not <$> liftEffect (Stream.closed stream)
+      pure unit
 
 -- | Reads a parsed record from the stream.
 -- |