chore: adds sync option to disable window syncing

README.md

@@ -58,7 +58,7 @@ export default Ember.Component.extend({
 
 #### Namespace & keyDelimiter
 
-In you apps `config/environment.js` you can set a `namespace` and a `keyDelimiter`. For backward compatibility this is a opt-in feature.
+In your `config/environment.js` you can set a `namespace` and a `keyDelimiter` option. For backward compatibility this is a opt-in feature.
 
 **Important:** Don't turn this feature on for existing apps. You will lose access to existing keys.
 
@@ -81,6 +81,24 @@ module.exports = function() {
 };
 ```
 
+#### Window Sync
+
+In your `config/environment.js` you can set a `sync` option. For backward compatibility this is a opt-in feature and defaults to true.
+
+If set to `false`, this will disable immediate syncing across tabs/windows.
+
+```js
+// config/environment.js
+module.exports = function() {
+  var ENV = {
+    modulePrefix: 'my-app',
+    'ember-local-storage': {
+      sync: true // disable syncing across windows
+    }
+  }
+};
+```
+
 #### ember-data support
 
 This addon autodetects if you use ember-data and will include the support for ember-data adapters and serializes by default. You can opt out of this behavior by setting the `includeEmberDataSupport` option to `false`:

addon/helpers/storage.js

@@ -77,9 +77,12 @@ function createStorage(context, key, modelKey) {
   const storageKey = modelKey
     ? `${storageFactory}:${modelKey}`
     : storageFactory;
+  let appConfig = owner.resolveRegistration('config:environment');
+  let addonConfig = (appConfig && appConfig['ember-local-storage']) || {};
 
   const defaultState = {
     _storageKey: _buildKey(context, storageKey),
+    _sync: _getSync(appConfig, addonConfig),
   };
   const StorageFactory = owner.factoryFor(storageFactory);
 
@@ -130,6 +133,17 @@ function _getNamespace(appConfig, addonConfig) {
   return namespace;
 }
 
+function _getSync(appConfig, addonConfig) {
+  // For backward compatibility this is a opt-in feature
+  let sync = addonConfig.sync;
+
+  if (sync === undefined) {
+    sync = appConfig.sync;
+  }
+
+  return sync;
+}
+
 // TODO: Add migration helper
 function _buildKey(context, key) {
   let appConfig = getOwner(context).resolveRegistration('config:environment');

addon/mixins/storage.js

@@ -21,6 +21,7 @@ export default Mixin.create({
     const storage = this._storage();
     const storageKey = get(this, '_storageKey');
     const initialContent = get(this, '_initialContent');
+    const sync = get(this, '_sync');
 
     let serialized, content;
 
@@ -39,7 +40,9 @@ export default Mixin.create({
     this.set('content', content);
 
     // Keep in sync with other windows
-    this._addStorageListener();
+    if (sync !== false) {
+      this._addStorageListener();
+    }
 
     return this._super(...arguments);
   },