1 files changed, 42 insertions, 0 deletions
diff --git a/app/assets/javascripts/visual_review_toolbar/shared/storage_utils.js b/app/assets/javascripts/visual_review_toolbar/shared/storage_utils.js
new file mode 100644
index 00000000000..00456d3536e
--- /dev/null
+++ b/app/assets/javascripts/visual_review_toolbar/shared/storage_utils.js
@@ -0,0 +1,42 @@
+import { setUsingGracefulStorageFlag } from '../store/state';
+
+const TEST_KEY = 'gitlab-storage-test';
+
+const createStorageStub = () => {
+  const items = {};
+
+  return {
+    getItem(key) {
+      return items[key];
+    },
+    setItem(key, value) {
+      items[key] = value;
+    },
+    removeItem(key) {
+      delete items[key];
+    },
+  };
+};
+
+const hasStorageSupport = storage => {
+  // Support test taken from https://stackoverflow.com/a/11214467/1708147
+  try {
+    storage.setItem(TEST_KEY, TEST_KEY);
+    storage.removeItem(TEST_KEY);
+    setUsingGracefulStorageFlag(true);
+
+    return true;
+  } catch (err) {
+    setUsingGracefulStorageFlag(false);
+    return false;
+  }
+};
+
+const useGracefulStorage = storage =>
+  // If a browser does not support local storage, let's return a graceful implementation.
+  hasStorageSupport(storage) ? storage : createStorageStub();
+
+const localStorage = useGracefulStorage(window.localStorage);
+const sessionStorage = useGracefulStorage(window.sessionStorage);
+
+export { localStorage, sessionStorage };