Add flushSync

Author: pete-murphy

src/React/Basic/DOM.js

@@ -19,3 +19,7 @@ export function unmount(node) {
 export function createPortal(jsx) {
   return (node) => ReactDOM.createPortal(jsx, node);
 }
+
+export function flushSync(callback) {
+  return () => ReactDOM.flushSync(callback);
+}

src/React/Basic/DOM.purs

@@ -100,4 +100,15 @@ foreign import createPortal :: JSX -> Element -> JSX
 
 -- | Create a text node.
 text :: String -> JSX
-text = unsafeCoerce
+text = unsafeCoerce
+
+-- | `flushSync` lets you force React to flush any updates inside the provided
+-- | callback synchronously. This ensures that the DOM is updated immediately.
+-- | 
+-- | ```purs
+-- | let
+-- |   handleNewChatMessage msg = do
+-- |     flushSync (setMessages (_ <> [msg]))
+-- |     scrollToLastMessage
+-- | ```
+foreign import flushSync :: forall a. Effect a -> Effect a