Merge branch 'with-ghcjs' into 'master'

Use Haskell on the frontend

See merge request guyonvarch/shared-cost!2

1 files changed, 17 insertions, 0 deletions

diff --git a/client/src/Util/WaitFor.hs b/client/src/Util/WaitFor.hs
new file mode 100644
index 0000000..fe7b733
--- /dev/null
+++ b/client/src/Util/WaitFor.hs
@@ -0,0 +1,17 @@
+module Util.WaitFor
+  ( waitFor
+  ) where
+
+import           Data.Time  (NominalDiffTime)
+import           Reflex.Dom (Dynamic, Event, MonadWidget)
+import qualified Reflex.Dom as R
+
+waitFor
+  :: forall t m a b. MonadWidget t m
+  => (Event t a -> m (Event t b))
+  -> Event t a
+  -> m (Event t b, Event t Bool)
+waitFor op input = do
+  result <- op input >>= R.debounce (0.5 :: NominalDiffTime)
+  let waiting = R.leftmost [ True <$ input , False <$ result ]
+  return (result, waiting)