Extract parsing JSON from localStorage into method

Author: galfert

src/dropbox.js

@@ -46,6 +46,7 @@ const isFolder = util.isFolder;
 const cleanPath = util.cleanPath;
 const shouldBeTreatedAsBinary = util.shouldBeTreatedAsBinary;
 const readBinaryData = util.readBinaryData;
+const getJSONFromLocalStorage = util.getJSONFromLocalStorage;
 
 /**
  * Map a local path to a path in Dropbox.
@@ -180,16 +181,11 @@ var Dropbox = function (rs) {
   hasLocalStorage = util.localStorageAvailable();
 
   if (hasLocalStorage){
-    var settings;
-    try {
-      settings = JSON.parse(localStorage.getItem(SETTINGS_KEY));
-    } catch(e) { /* ok to ignore, probably no data in localStorage */ }
+    const settings = getJSONFromLocalStorage(SETTINGS_KEY);
     if (settings) {
       this.configure(settings);
     }
-    try {
-      this._itemRefs = JSON.parse(localStorage.getItem(SETTINGS_KEY+':shares')) || {};
-    } catch(e) { /* ok to ignore, no shares in localStorage */ }
+    this._itemRefs = getJSONFromLocalStorage(`${SETTINGS_KEY}:shares`) || {};
   }
   if (this.connected) {
     setTimeout(this._emit.bind(this), 0, 'connected');

src/googledrive.js

@@ -33,6 +33,7 @@ const isFolder = util.isFolder;
 const cleanPath = util.cleanPath;
 const shouldBeTreatedAsBinary = util.shouldBeTreatedAsBinary;
 const readBinaryData = util.readBinaryData;
+const getJSONFromLocalStorage = util.getJSONFromLocalStorage;
 
 let hasLocalStorage;
 
@@ -142,12 +143,7 @@ const GoogleDrive = function (remoteStorage, clientId) {
   hasLocalStorage = util.localStorageAvailable();
 
   if (hasLocalStorage){
-    let settings;
-    try {
-      settings = JSON.parse(localStorage.getItem(SETTINGS_KEY));
-    } catch(e) {
-      // no settings stored
-    }
+    const settings = getJSONFromLocalStorage(SETTINGS_KEY);
     if (settings) {
       this.configure(settings);
     }

src/remotestorage.js

@@ -12,6 +12,7 @@ const log = require('./log');
 const Features = require('./features');
 const globalContext = util.getGlobalContext();
 const eventHandling = require('./eventhandling');
+const getJSONFromLocalStorage = util.getJSONFromLocalStorage;
 
 var hasLocalStorage;
 
@@ -90,11 +91,7 @@ var RemoteStorage = function (cfg) {
   hasLocalStorage = util.localStorageAvailable();
 
   if (hasLocalStorage) {
-    try {
-      this.apiKeys = JSON.parse(localStorage.getItem('remotestorage:api-keys')) || {};
-    } catch(exc) {
-      // ignored
-    }
+    this.apiKeys = getJSONFromLocalStorage('remotestorage:api-keys') || {};
     this.setBackend(localStorage.getItem('remotestorage:backend') || 'remotestorage');
   }
 

src/util.js

@@ -242,6 +242,23 @@ var util = {
     }
   },
 
+  /**
+   * Extract and parse JSON data from localStorage.
+   *
+   * @param {string} key - localStorage key
+   *
+   * @returns {object} parsed object or undefined
+   */
+  getJSONFromLocalStorage (key) {
+    const context = util.getGlobalContext();
+
+    try {
+      return JSON.parse(context.localStorage.getItem(key));
+    } catch(e) {
+      // no JSON stored
+    }
+  },
+
   /**
    * Decide if data should be treated as binary based on the content
    * and content-type.

src/wireclient.js

@@ -75,6 +75,7 @@ if (typeof(ArrayBufferView) === 'function') {
 const isFolder = util.isFolder;
 const cleanPath = util.cleanPath;
 const shouldBeTreatedAsBinary = util.shouldBeTreatedAsBinary;
+const getJSONFromLocalStorage = util.getJSONFromLocalStorage;
 
 function addQuotes(str) {
   if (typeof(str) !== 'string') {
@@ -167,12 +168,7 @@ var WireClient = function WireClient(rs) {
   eventHandling(this, 'connected', 'not-connected');
 
   if (hasLocalStorage) {
-    var settings;
-    try {
-      settings = JSON.parse(localStorage[SETTINGS_KEY]);
-    } catch(e) {
-      // no settings stored
-    }
+    const settings = getJSONFromLocalStorage(SETTINGS_KEY);
     if (settings) {
       setTimeout(function () {
         this.configure(settings);

test/unit/util-suite.js

@@ -151,6 +151,34 @@ define(['./src/util'], function (util) {
 
           test.assert(util.localStorageAvailable(), false);
         }
+      },
+
+      {
+        desc: "getJSONFromLocalStorage returns the object for the given key",
+        run: function(env, test) {
+
+          global.localStorage = {
+            getItem: function() {
+              return '{ "foo": "bar" }';
+            }
+          };
+
+          test.assert(util.getJSONFromLocalStorage('somekey'), { foo: 'bar' });
+        }
+      },
+
+      {
+        desc: "getJSONFromLocalStorage returns null when there is no object for the given key",
+        run: function(env, test) {
+
+          global.localStorage = {
+            getItem: function() {
+              return null;
+            }
+          };
+
+          test.assert(util.getJSONFromLocalStorage('somekey'), null);
+        }
       }
 
     ]