1 files changed, 16 insertions, 0 deletions
diff --git a/devtools/client/shared/redux/subscriber.js b/devtools/client/shared/redux/subscriber.js
new file mode 100644
index 0000000000..39b0823770
--- /dev/null
+++ b/devtools/client/shared/redux/subscriber.js
@@ -0,0 +1,16 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at <http://mozilla.org/MPL/2.0/>. */
+
+"use strict";
+
+function registerStoreObserver(store, subscriber) {
+  let oldState = store.getState();
+  store.subscribe(() => {
+    const state = store.getState();
+    subscriber(state, oldState);
+    oldState = state;
+  });
+}
+
+exports.registerStoreObserver = registerStoreObserver;