Added count and exists

Author: tmpaul

README.md

@@ -1,4 +1,4 @@
-##JugglingDB Adapter for DynamoDB version 0.1.9-4
+##JugglingDB Adapter for DynamoDB version 0.1.9-5
 * Adapter is still in development stage. The stable release will be 0.2.0 and will offer rich functionalities along
 with lots of tests.
 * Always use the latest version of this adapter, preferably >= 0.1.5. The latest version has more features and lots of bug fixes. Versions

lib/dynamodb.js

@@ -1232,7 +1232,7 @@ DynamoDB.prototype.all = function all(model, filter, callback) {
                 callback(null, queryResults);
                 logger.log("debug", "Query complete");
               }
-          }     
+          }
       }.bind(this));
   }
 };
@@ -1856,3 +1856,41 @@ DynamoDB.prototype.destroyAll = function(model, callback) {
     });
   logger.log("warn", t.bold.red, stopTimer(timeStart).bold.cyan);
 };
+
+/**
+ * Get number of records matching a filter
+ * @param  {Object}   model    
+ * @param  {Function} callback 
+ * @param  {Object}   where    : Filter
+ * @return {Number}            : Number of matching records
+ */
+DynamoDB.prototype.count = function count(model, callback, where) {
+  var filter = {};
+  filter.where = where;
+  this.all(model, filter, function(err, results){
+    if (err || !results) {
+      callback(err, null);
+    } else {
+      callback(null, results.length);
+    }
+  });
+};
+
+/**
+ * Check if a given record exists
+ * @param  {[type]}   model    [description]
+ * @param  {[type]}   id       [description]
+ * @param  {Function} callback [description]
+ * @return {[type]}            [description]
+ */
+DynamoDB.prototype.exists = function exists(model, id, callback) {
+  this.find(model, id, function (err, record){
+    if (err) {
+      callback(err, null);
+    } else if(isEmpty(record)) {
+      callback(null, false);
+    } else {
+      callback(null, true);
+    }
+  });
+};

package.json

@@ -1,7 +1,7 @@
 {
   "name": "jugglingdb-dynamodb",
   "description": "DynamoDB adapter for JugglingDB ORM",
-  "version": "0.1.9-4",
+  "version": "0.1.9-5",
   "main": "index.js",
   "scripts": {
     "test": "make test",

test/basic-querying.test.js

@@ -25,7 +25,7 @@ describe('basic-querying', function() {
     describe('find', function() {
 
         before(function(done) {
-		done();
+            done();
         });
 
         it('should query by id: not found', function(done) {
@@ -45,7 +45,7 @@ describe('basic-querying', function() {
                     should.not.exist(err);
                     u.should.be.an.instanceOf(User);
 					u.destroy(function(err) {
-            done();
+                        done();
 					});
 
                 });
@@ -140,6 +140,28 @@ describe('basic-querying', function() {
 
     });
 
+    describe('count', function() {
+
+        before(seed);
+
+        it('should query total count', function(done) {
+            User.count(function(err, n) {
+                should.not.exist(err);
+                should.exist(n);
+                n.should.equal(6);
+                done();
+            });
+        });
+
+        it('should query filtered count', function(done) {
+            User.count({role: 'lead'}, function(err, n) {
+                should.not.exist(err);
+                should.exist(n);
+                n.should.equal(2);
+                done();
+            });
+        });
+    });
 
     describe('findOne', function() {
 
@@ -158,6 +180,35 @@ describe('basic-querying', function() {
     });
 });
 
+
+
+    describe('exists', function() {
+
+        before(seed);
+
+        it('should check whether record exist', function(done) {
+            User.findOne(function(e, u) {
+                User.exists(u.id, function(err, exists) {
+                    should.not.exist(err);
+                    should.exist(exists);
+                    exists.should.be.ok;
+                    done();
+                });
+            });
+        });
+
+        it('should check whether record not exist', function(done) {
+            User.destroyAll(function() {
+                User.exists("asdasd", function(err, exists) {
+                    should.not.exist(err);
+                    exists.should.not.be.ok;
+                    done();
+                });
+            });
+        });
+
+    });
+
 function seed(done) {
     var count = 0;
     var beatles = [
@@ -180,9 +231,11 @@ function seed(done) {
         {name: 'Stuart Sutcliffe', order: 3}
     ];
 
+    User.destroyAll(function() {
         beatles.forEach(function(beatle) {
             User.create(beatle, ok);
         });
+    });
 
 
     function ok() {