planning

node_modules/react-topbar-progress-indicator/src/index.js

@@ -0,0 +1,47 @@
+// @flow
+
+var React = require("react");
+
+// topbar require window, so here is an universal workaround
+var topbar =
+  typeof window === "undefined"
+    ? {
+        show: function() {},
+        hide: function() {},
+        config: function() {}
+      }
+    : require("topbar");
+
+var semaphore /*: number*/ = 0;
+
+/*::
+type Props = {
+  topbar?: typeof topbar
+};
+*/
+
+var getTopBar = function(props /*: Props*/) /*: typeof topbar*/ {
+  return props.topbar || topbar;
+};
+
+function TopBar(props /*: Props */) {
+  React.useEffect(function() {
+    if (semaphore === 0) {
+      getTopBar(props).show();
+    }
+    semaphore++;
+
+    return function() {
+      semaphore--;
+      if (semaphore === 0) {
+        getTopBar(props).hide();
+      }
+    };
+  }, []);
+
+  return null;
+}
+
+TopBar.config = topbar.config;
+
+module.exports = TopBar;