Merge pull request #14 from mattpowell/master

Basic bucketing support

README.markdown

@@ -38,6 +38,12 @@ Removes a value from localStorage.
 ### lscache.flush
 Removes all lscache items from localStorage without affecting other data.
 
+* * *
+
+### lscache.setBucket
+Appends CACHE_PREFIX so lscache will partition data in to different buckets
+#### Arguments
+1. `bucket` (**string**)
 
 Usage
 -------
@@ -80,6 +86,15 @@ And then when you retrieve it, you will get it back as an object:
 alert(lscache.get('data').name);
 ```
 
+If you have multiple instances of lscache running on the same domain, you can partition data in a certain bucket via:
+
+```js
+lscache.set('response', '...', 2);
+lscache.setBucket('lib');
+lscache.set('path', '...', 2);
+lscache.flush(); //only removes 'path' which was set in the lib bucket
+```
+
 For more live examples, play around with the demo here:
 http://pamelafox.github.com/lscache/demo.html
 

lscache.js

@@ -39,6 +39,7 @@ var lscache = function() {
 
   var cachedStorage;
   var cachedJSON;
+  var cacheBucket = '';
 
   // Determines if localStorage is supported in the browser;
   // result is cached for better performance instead of being run each time.
@@ -94,17 +95,17 @@ var lscache = function() {
    */
 
   function getItem(key) {
-    return localStorage.getItem(CACHE_PREFIX + key);
+    return localStorage.getItem(CACHE_PREFIX + cacheBucket + key);
   }
 
   function setItem(key, value) {
     // Fix for iPad issue - sometimes throws QUOTA_EXCEEDED_ERR on setItem.
-    localStorage.removeItem(CACHE_PREFIX + key);
-    localStorage.setItem(CACHE_PREFIX + key, value);
+    localStorage.removeItem(CACHE_PREFIX + cacheBucket + key);
+    localStorage.setItem(CACHE_PREFIX + cacheBucket + key, value);
   }
 
   function removeItem(key) {
-    localStorage.removeItem(CACHE_PREFIX + key);
+    localStorage.removeItem(CACHE_PREFIX + cacheBucket + key);
   }
 
   return {
@@ -143,8 +144,8 @@ var lscache = function() {
           for (var i = 0; i < localStorage.length; i++) {
             storedKey = localStorage.key(i);
 
-            if (storedKey.indexOf(CACHE_PREFIX) === 0 && storedKey.indexOf(CACHE_SUFFIX) < 0) {
-              var mainKey = storedKey.substr(CACHE_PREFIX.length);
+            if (storedKey.indexOf(CACHE_PREFIX + cacheBucket) === 0 && storedKey.indexOf(CACHE_SUFFIX) < 0) {
+              var mainKey = storedKey.substr((CACHE_PREFIX + cacheBucket).length);
               var exprKey = expirationKey(mainKey);
               var expiration = getItem(exprKey);
               if (expiration) {
@@ -258,10 +259,25 @@ var lscache = function() {
       // Loop in reverse as removing items will change indices of tail
       for (var i = localStorage.length-1; i >= 0 ; --i) {
         var key = localStorage.key(i);
-        if (key.indexOf(CACHE_PREFIX) === 0) {
+        if (key.indexOf(CACHE_PREFIX + cacheBucket) === 0) {
           localStorage.removeItem(key);
         }
       }
+    },
+    
+    /**
+     * Appends CACHE_PREFIX so lscache will partition data in to different buckets.
+     * @param {string} bucket
+     */
+    setBucket: function(bucket) {
+      cacheBucket = bucket;
+    },
+    
+    /**
+     * Resets the string being appended to CACHE_PREFIX so lscache will use the default storage behavior.
+     */
+    resetBucket: function() {
+      cacheBucket = '';
     }
   };
 }();

test.html

@@ -68,6 +68,23 @@
   equals(localStorage.getItem('outside-cache'), 'not part of lscache', 'We expect localStorage value to still persist');
 });
 
+test('Testing setBucket()', function() {
+  var key = 'thekey';
+  var value1 = 'awesome';
+  var value2 = 'awesomer';
+  var bucketName = 'BUCKETONE';
+      
+  lscache.set(key, value1, 1);
+  lscache.setBucket(bucketName);
+  lscache.set(key, value2, 1);
+  
+  equals(lscache.get(key), value2, 'We expect "' + value2 + '" to be returned for the current bucket: ' + bucketName);
+  lscache.flush();
+  equals(lscache.get(key), null, 'We expect "' + value2 + '" to be flushed for the current bucket');
+  lscache.resetBucket();
+  equals(lscache.get(key), value1, 'We expect "' + value1 + '", the non-bucket value, to persist');
+});
+
 test('Testing quota exceeding', function() {
   var key = 'thekey';
 
@@ -117,7 +134,7 @@
 asyncTest('Testing set() and get() with string and expiration', 1, function() {
 
   var key = 'thekey';
-  var value = 'thevalue'
+  var value = 'thevalue';
   var minutes = 1;
   lscache.set(key, value, minutes);
   setTimeout(function() {
@@ -126,6 +143,24 @@
   }, 1000*60*minutes);
 });
 
+asyncTest('Testing set() and get() with string and expiration in a different bucket', 2, function() {
+
+  var key = 'thekey';
+  var value1 = 'thevalue1';
+  var value2 = 'thevalue2';
+  var minutes = 1;
+  var bucket = 'newbucket';
+  lscache.set(key, value1, minutes * 2);
+  lscache.setBucket(bucket);
+  lscache.set(key, value2, minutes);
+  setTimeout(function() {
+    equals(lscache.get(key), null, 'We expect value to be null for the bucket: ' + bucket);
+    lscache.resetBucket();
+    equals(lscache.get(key), value1, 'We expect value to be ' + value1 + ' for the base bucket.');
+    start();
+  }, 1000*60*minutes);
+});
+
 }
 
   </script>