Guard from invalid value on local storage

src/infrastructure/PreferenceStorage.js

@@ -0,0 +1,34 @@
+export default class PreferenceStorage {
+  constructor(key) {
+    this.key = key;
+  }
+
+  get() {
+    try {
+      return JSON.parse(localStorage.getItem(this.key));
+    } catch (e) {
+      console.warn(e);
+      return null;
+    }
+  }
+
+  save(json) {
+    localStorage.setItem(this.key, JSON.stringify(json));
+  }
+
+  remove() {
+    localStorage.removeItem(this.key);
+  }
+
+  poll() {
+    return new Promise(resolve => {
+      const callback = e => {
+        if (e.storageArea === localStorage && e.key === this.key && e.newValue !== null) {
+          window.removeEventListener('storage', callback);
+          resolve();
+        }
+      }
+      window.addEventListener('storage', callback);
+    });
+  }
+}

src/repositories/AppPreferenceRepository.js

@@ -1,27 +1,27 @@
+import PreferenceStorage from '../infrastructure/PreferenceStorage';
+
 import AppPreference from '../models/AppPreference';
 import { THEMES } from '../models/Themes';
 
-const APP_PREFERENCE = 'APP_PREFERENCE';
-const SELECTED_THEME_ID = 'SELECTED_THEME_ID';
-const HIDDEN_COMPONENTS = 'HIDDEN_COMPONENTS';
-
 export default class AppPreferenceRepository {
-  get() {
-    const oldSelectedThemeId = JSON.parse(localStorage.getItem(SELECTED_THEME_ID));
-    const json = JSON.parse(localStorage.getItem(APP_PREFERENCE));
+  preferenceStorage = new PreferenceStorage('APP_PREFERENCE')
+  oldHiddenComponentsStorage = new PreferenceStorage('HIDDEN_COMPONENTS')
+  oldSelectedThemeIdStorage = new PreferenceStorage('SELECTED_THEME_ID')
 
-    const theme = THEMES.getById(this.extractThemeIdFrom(json, oldSelectedThemeId));
-    return new AppPreference({...json, theme});
+  get() {
+    const json = this.preferenceStorage.get();
+    return this.migrateOldKey(new AppPreference({
+      ...json,
+      theme: THEMES.getById(json ? json.theme : null)
+    }));
   }
 
-  extractThemeIdFrom(json, oldSelectedThemeId) {
-    if (oldSelectedThemeId) {
-      // migrate old key
-      return oldSelectedThemeId;
-    } else if (json) {
-      return json.theme;
+  migrateOldKey(appPreference) {
+    const selectedThemeId = this.oldSelectedThemeIdStorage.get();
+    if (selectedThemeId !== null) {
+      return appPreference.set('theme', THEMES.getById(selectedThemeId));
     } else {
-      return null;
+      return appPreference;
     }
   }
 
@@ -39,22 +39,14 @@ export default class AppPreferenceRepository {
             return value;
         }
       });
-    localStorage.setItem(APP_PREFERENCE, JSON.stringify(json));
+    this.preferenceStorage.save(json);
 
-    // clean up old key
-    localStorage.removeItem(HIDDEN_COMPONENTS);
-    localStorage.removeItem(SELECTED_THEME_ID);
+    // remove old data
+    this.oldHiddenComponentsStorage.remove();
+    this.oldSelectedThemeIdStorage.remove();
   }
 
   poll() {
-    return new Promise(resolve => {
-      const callback = e => {
-        if (e.storageArea === localStorage && e.key === APP_PREFERENCE && e.newValue !== null) {
-          window.removeEventListener('storage', callback);
-          resolve();
-        }
-      }
-      window.addEventListener('storage', callback);
-    });
+    return this.preferenceStorage.poll();
   }
 }

src/repositories/FolderItemPreferenceRepository.js

@@ -1,30 +1,25 @@
 import { Seq } from 'immutable';
+import PreferenceStorage from '../infrastructure/PreferenceStorage';
 
 import FolderItemPreference from '../models/FolderItemPreference';
 import FolderItemPreferences from '../models/FolderItemPreferences';
 
-const FOLDER_ITEM_PREFERENCES = 'FOLDER_ITEM_PREFERENCES';
-
 export default class FolderItemPreferenceRepository {
+  preferenceStorage = new PreferenceStorage('FOLDER_ITEM_PREFERENCES');
+
   get() {
-    const json = JSON.parse(localStorage.getItem(FOLDER_ITEM_PREFERENCES));
-    const array = Seq(json).map(object => new FolderItemPreference(object)).toArray();
-    return new FolderItemPreferences(array);
+    const json = this.preferenceStorage.get();
+    const arrayOfFolderItemPreference = Seq(json)
+      .map(object => new FolderItemPreference(object))
+      .toArray();
+    return new FolderItemPreferences(arrayOfFolderItemPreference);
   }
 
   save(folderItemPreferences) {
-    localStorage.setItem(FOLDER_ITEM_PREFERENCES, JSON.stringify(folderItemPreferences.toArray()));
+    this.preferenceStorage.save(folderItemPreferences.toArray());
   }
 
   poll() {
-    return new Promise(resolve => {
-      const callback = e => {
-        if (e.storageArea === localStorage && e.key === FOLDER_ITEM_PREFERENCES && e.newValue !== null) {
-          window.removeEventListener('storage', callback);
-          resolve();
-        }
-      }
-      window.addEventListener('storage', callback);
-    });
+    return this.preferenceStorage.poll();
   }
 }

src/repositories/FolderPreferenceRepository.js

@@ -1,39 +1,38 @@
 import { Seq } from 'immutable';
+import PreferenceStorage from '../infrastructure/PreferenceStorage';
 
 import FolderPreference from '../models/FolderPreference';
 import FolderPreferences from '../models/FolderPreferences';
 
-const FOLDER_PREFERENCES = 'FOLDER_PREFERENCES';
-const COLLAPSED_FOLDERS = 'COLLAPSED_FOLDERS';
-
 export default class FolderPreferenceRepository {
+  preferenceStorage = new PreferenceStorage('FOLDER_PREFERENCES')
+  oldCollapsedFoldersStorage = new PreferenceStorage('COLLAPSED_FOLDERS')
+
   get() {
     // migrate old data
-    if (localStorage.getItem(COLLAPSED_FOLDERS)) {
-      const json = JSON.parse(localStorage.getItem(COLLAPSED_FOLDERS));
-      const array = Seq(json).map(id => new FolderPreference({id, collapsed: true})).toArray();
-      return new FolderPreferences(array);
+    const collapsedFolders = this.oldCollapsedFoldersStorage.get();
+    if (collapsedFolders !== null) {
+      const arrayOfFolderPreferences = Seq(collapsedFolders)
+        .map(id => new FolderPreference({id, collapsed: true}))
+        .toArray();
+      return new FolderPreferences(arrayOfFolderPreferences);
     }
 
-    const json = JSON.parse(localStorage.getItem(FOLDER_PREFERENCES));
-    const array = Seq(json).map(object => new FolderPreference(object)).toArray();
-    return new FolderPreferences(array);
+    const json = this.preferenceStorage.get();
+    const arrayOfFolderPreferences = Seq(json)
+      .map(object => new FolderPreference(object))
+      .toArray();
+    return new FolderPreferences(arrayOfFolderPreferences);
   }
 
   save(folderPreferences) {
-    localStorage.setItem(FOLDER_PREFERENCES, JSON.stringify(folderPreferences.toArray()));
-    localStorage.removeItem(COLLAPSED_FOLDERS);
+    this.preferenceStorage.save(folderPreferences.toArray());
+
+    // remove old data
+    this.oldCollapsedFoldersStorage.remove();
   }
 
   poll() {
-    return new Promise(resolve => {
-      const callback = e => {
-        if (e.storageArea === localStorage && e.key === FOLDER_PREFERENCES && e.newValue !== null) {
-          window.removeEventListener('storage', callback);
-          resolve();
-        }
-      }
-      window.addEventListener('storage', callback);
-    });
+    return this.preferenceStorage.poll();
   }
 }