Pre-alpha: React with any emoji, behind flag

ts/util/hooks.ts

@@ -0,0 +1,42 @@
+import * as React from 'react';
+import { ActionCreatorsMapObject, bindActionCreators } from 'redux';
+import { useDispatch } from 'react-redux';
+
+// Restore focus on teardown
+export const useRestoreFocus = (
+  // The ref for the element to receive initial focus
+  focusRef: React.RefObject<any>,
+  // Allow for an optional root element that must exist
+  root: boolean | HTMLElement | null = true
+) => {
+  React.useEffect(() => {
+    if (!root) {
+      return;
+    }
+
+    const lastFocused = document.activeElement as any;
+    if (focusRef.current) {
+      focusRef.current.focus();
+    }
+
+    return () => {
+      // This ensures that the focus is returned to
+      // previous element
+      setTimeout(() => {
+        if (lastFocused && lastFocused.focus) {
+          lastFocused.focus();
+        }
+      });
+    };
+  }, [focusRef, root]);
+};
+
+export const useBoundActions = <T extends ActionCreatorsMapObject>(
+  actions: T
+) => {
+  const dispatch = useDispatch();
+
+  return React.useMemo(() => {
+    return bindActionCreators(actions, dispatch);
+  }, [dispatch]);
+};