#316: add localStorage wrapper with feature detection

.eslintrc.json

@@ -113,6 +113,10 @@
         "no-undef-init": "error",
         "no-undef": "error",
         "no-use-before-define": ["warn", "nofunc"],
+        "no-restricted-globals": ["error",
+            "localStorage", "sessionStorage", // we have our own localStorage module
+            "event"
+        ],
 
         // CommonJS
         "no-mixed-requires": "warn",

src/components/auth/actions.js

@@ -1,6 +1,7 @@
 import { routeActions } from 'react-router-redux';
 
 import logger from 'services/logger';
+import localStorage from 'services/localStorage';
 import loader from 'services/loader';
 import history from 'services/history';
 import { updateUser, acceptRules as userAcceptRules } from 'components/user/actions';

src/services/authFlow/AuthFlow.js

@@ -1,6 +1,7 @@
 import { routeActions } from 'react-router-redux';
 
 import logger from 'services/logger';
+import localStorage from 'services/localStorage';
 
 import RegisterState from './RegisterState';
 import LoginState from './LoginState';

src/services/localStorage.js

@@ -0,0 +1,40 @@
+import logger from 'services/logger';
+
+let _hasStorage = false;
+
+try {
+    const test = 'test';
+    window.localStorage.setItem(test, test);
+    window.localStorage.removeItem(test);
+
+    _hasStorage = true;
+} catch (err) {
+    // bad luck, no storage available
+    logger.info('No storage available'); // log for statistic purposes
+}
+
+export function hasStorage() {
+    return _hasStorage;
+}
+
+function DummyStorage() {
+    return {
+        getItem(key) {
+            return this[key] || null;
+        },
+
+        setItem(key, value) {
+            this[key] = value;
+        },
+
+        removeItem(key) {
+            Reflect.deleteProperty(this, key);
+        }
+    };
+}
+
+export const localStorage = _hasStorage ? window.localStorage : new DummyStorage();
+
+export const sessionStorage = _hasStorage ? window.sessionStorage : new DummyStorage();
+
+export default localStorage;