Merge pull request #4128 from sequelize/feat-count-btm-associations

feat(belongs-to-many): countAssociations

lib/associations/belongs-to-many.js

@@ -272,7 +272,17 @@ var BelongsToMany = function(source, target, options) {
      * @return {Promise}
      * @method hasAssociations
      */
-    hasAll: 'has' + plural
+    hasAll: 'has' + plural,
+    /**
+     * Count everything currently associated with this, using an optional where clause
+     *
+     * @param {Object} [options]
+     * @param {Object} [options.where] An optional where clause to limit the associated models
+     * @param {String|Boolean} [options.scope] Apply a scope on the related model, or remove its default scope by passing false
+     * @return {Promise<Int>}
+     * @method countAssociations
+     */
+    count: 'count' + plural
   };
 
   if (this.options.counterCache) {
@@ -393,10 +403,8 @@ BelongsToMany.prototype.injectGetter = function(obj) {
       throughWhere = {};
       throughWhere[association.identifier] = instance.get(association.source.primaryKeyAttribute);
 
-      if (through && through.scope) {
-        Object.keys(through.scope).forEach(function (attribute) {
-          throughWhere[attribute] = through.scope[attribute];
-        }.bind(this));
+      if (through.scope) {
+        _.assign(throughWhere, through.scope);
       }
 
       options.include = options.include || [];
@@ -429,6 +437,23 @@ BelongsToMany.prototype.injectGetter = function(obj) {
     return model.findAll(options);
   };
 
+  obj[this.accessors.count] = function(options) {
+    var model = association.target
+      , sequelize = model.sequelize;
+
+    options = association.target.__optClone(options) || {};
+    options.attributes = [
+      [sequelize.fn('COUNT', sequelize.col(model.primaryKeyAttribute)), 'count']
+    ];
+    options.joinTableAttributes = [];
+    options.raw = true;
+    options.plain = true;
+
+    return obj[association.accessors.get].call(this, options).then(function (result) {
+      return parseInt(result.count, 10);
+    });
+  };
+
   obj[this.accessors.hasSingle] = obj[this.accessors.hasAll] = function(instances, options) {
     var where = {};
 

test/integration/associations/belongs-to-many.test.js

@@ -31,6 +31,7 @@ describe(Support.getTestDialectTeaser('BelongsToMany'), function() {
         ]);
       }).spread(function(john, task1, task2) {
         self.tasks = [task1, task2];
+        self.user = john;
         return john.setTasks([task1, task2]);
       });
     });
@@ -410,6 +411,54 @@ describe(Support.getTestDialectTeaser('BelongsToMany'), function() {
     });
   });
 
+  describe('countAssociations', function() {
+    beforeEach(function() {
+      var self = this;
+
+      this.User = this.sequelize.define('User', { username: DataTypes.STRING });
+      this.Task = this.sequelize.define('Task', { title: DataTypes.STRING, active: DataTypes.BOOLEAN });
+
+      this.User.belongsToMany(this.Task, { through: 'UserTasks' });
+      this.Task.belongsToMany(this.User, { through: 'UserTasks' });
+
+      return this.sequelize.sync({ force: true }).then(function() {
+        return Promise.all([
+          self.User.create({ username: 'John'}),
+          self.Task.create({ title: 'Get rich', active: true}),
+          self.Task.create({ title: 'Die trying', active: false})
+        ]);
+      }).spread(function(john, task1, task2) {
+        self.tasks = [task1, task2];
+        self.user = john;
+        return john.setTasks([task1, task2]);
+      });
+    });
+
+    it('should count all associations', function () {
+      return expect(this.user.countTasks({})).to.eventually.equal(2);
+    });
+
+    it('should count filtered associations', function () {
+      return expect(this.user.countTasks({
+        where: {
+          active: true
+        }
+      })).to.eventually.equal(1);
+    });
+
+    it('should count scoped associations', function () {
+      this.User.belongsToMany(this.Task, {
+        as: 'activeTasks',
+        through: 'UserTasks',
+        scope: {
+          active: true
+        }
+      });
+
+      return expect(this.user.countActiveTasks({})).to.eventually.equal(1);
+    });
+  });
+
   describe('setAssociations', function() {
     it('clears associations when passing null to the set-method', function() {
       var User = this.sequelize.define('User', { username: DataTypes.STRING })