Add promise support for get/set

lib/multi_caching.js

@@ -64,7 +64,11 @@ var multiCaching = function(caches, options) {
 
                 if (_isCacheableValue(result)) {
                     // break out of async loop.
-                    return cb(err, result, i);
+                    if (typeof cb === 'function') {
+                        return cb(err, result, i);
+                    } else {
+                        return cb.resolve(result);
+                    }
                 }
 
                 i += 1;
@@ -72,7 +76,17 @@ var multiCaching = function(caches, options) {
             };
 
             cache.store.get(key, options, callback);
-        }, cb);
+        }, function(err, result) {
+            if (typeof cb === 'object') {
+                if (err) {
+                    cb.reject(err);
+                } else {
+                    cb.resolve(result);
+                }
+            } else if (typeof cb === 'function') {
+                cb(err, result);
+            }
+        });
     }
 
     function setInMultipleCaches(caches, opts, cb) {
@@ -85,7 +99,17 @@ var multiCaching = function(caches, options) {
             } else {
                 next();
             }
-        }, cb);
+        }, function(err, result) {
+            if (typeof cb === 'object') {
+                if (err) {
+                    cb.reject(err);
+                } else {
+                    cb.resolve(result);
+                }
+            } else if (typeof cb === 'function') {
+                cb(err, result);
+            }
+        });
     }
 
     /**
@@ -98,10 +122,18 @@ var multiCaching = function(caches, options) {
     self.getAndPassUp = function(key, cb) {
         getFromHighestPriorityCache(key, function(err, result, index) {
             if (err) {
-                return cb(err);
+                if (typeof cb === 'function') {
+                    return cb(err);
+                } else {
+                    return cb.reject(err);
+                }
             }
 
-            cb(err, result);
+            if (typeof cb === 'function') {
+                cb(err, result);
+            } else {
+                cb.resolve(result);
+            }
 
             if (index) {
                 var cachesToUpdate = caches.slice(0, index);
@@ -227,7 +259,11 @@ var multiCaching = function(caches, options) {
             options: options
         };
 
-        setInMultipleCaches(caches, opts, cb);
+        var defer = Promise.defer();
+
+        setInMultipleCaches(caches, opts, cb || defer);
+
+        return defer.promise;
     };
 
     /**
@@ -246,7 +282,11 @@ var multiCaching = function(caches, options) {
             options = {};
         }
 
-        getFromHighestPriorityCache(key, options, cb);
+        var defer = Promise.defer();
+
+        getFromHighestPriorityCache(key, options, cb || defer);
+
+        return defer.promise;
     };
 
     /**

lib/stores/memory.js

@@ -27,6 +27,8 @@ var memoryStore = function(args) {
         lruCache.set(key, value, maxAge);
         if (cb) {
             process.nextTick(cb);
+        } else {
+            return Promise.resolve(value);
         }
     };
 
@@ -35,6 +37,7 @@ var memoryStore = function(args) {
             cb = options;
         }
         var value = lruCache.get(key);
+
         if (cb) {
             process.nextTick(function() {
                 cb(null, value);

test/multi_caching.unit.js

@@ -181,6 +181,19 @@ describe("multiCaching", function() {
                     });
                 });
             });
+
+            describe('using promises', function() {
+                it('should return a promise and resolve it', function(done) {
+                    memoryCache3.set(key, value)
+                    .then(function() {
+                        return multiCache.get(key);
+                    })
+                    .then(function(result) {
+                        assert.equal(result, value);
+                    })
+                    .then(done);
+                });
+            });
         });
 
         describe("del()", function() {