Add sequelize.truncate function

Use truncate internal

changelog.md

 # Next
 - [FEATURE] Add support for keyword `after` in options of a field (useful for migrations), only for MySQL. [#3166](https://github.com/sequelize/sequelize/pull/3166)
+- [FEATURE] There's a new sequelize.truncate function to truncate all tables defined through the sequelize models [#2671](https://github.com/sequelize/sequelize/pull/2671)
 - [FIXED] Fix a case where `type` in `sequelize.query` was not being set to raw. [#3800](https://github.com/sequelize/sequelize/pull/3800)
 - [FIXED] Fix an issue where include all was not being properly expanded for self-references [#3804](https://github.com/sequelize/sequelize/issues/3804)
 - [FIXED] Fix instance.changed regression to not return false negatives for not changed null values [#3812](https://github.com/sequelize/sequelize/issues/3812)

lib/model.js

@@ -1441,6 +1441,23 @@ module.exports = (function() {
   };
 
   /**
+   * Truncate all instances of the model. This is a convenient method for Model.destroy({ truncate: true }).
+   *
+   * @param {object} [options] The options passed to Model.destroy in addition to truncate
+   * @param {Boolean|function} [options.transaction]
+   * @param {Boolean|function} [options.cascade = false] Only used in conjuction with TRUNCATE. Truncates  all tables that have foreign-key references to the named table, or to any tables added to the group due to CASCADE.
+   * @param {Boolean|function} [options.logging] A function that logs sql queries, or false for no logging
+   * @return {Promise}
+   *
+   * @see {Model#destroy} for more information
+   */
+  Model.prototype.truncate = function(options) {
+    options = options || {};
+    options.truncate = true;
+    return this.destroy(options);
+  };
+
+  /**
    * Delete multiple instances, or set their deletedAt timestamp to the current time if `paranoid` is enabled.
    *
    * @param  {Object}       options
@@ -1460,7 +1477,7 @@ module.exports = (function() {
       , instances;
 
     if (!options || !(options.where || options.truncate)) {
-      throw new Error('Missing where or truncate attribute in the options parameter passed to destroy.');
+      throw new Error('Missing where or truncate attribute in the options parameter of model.destroy.');
     }
 
     options = Utils._.extend({

lib/sequelize.js

@@ -902,6 +902,31 @@ module.exports = (function() {
   };
 
   /**
+   * Truncate all tables defined through the sequelize models. This is done
+   * by calling Model.truncate() on each model.
+   *
+   * @param {object} [options] The options passed to Model.destroy in addition to truncate
+   * @param {Boolean|function} [options.transaction]
+   * @param {Boolean|function} [options.logging] A function that logs sql queries, or false for no logging
+   * @return {Promise}
+   *
+   * @see {Model#truncate} for more information
+   */
+  Sequelize.prototype.truncate = function(options) {
+    var models = [];
+
+    this.modelManager.forEachModel(function(model) {
+      if (model) {
+        models.push(model);
+      }
+    }, { reverse: false });
+
+    return Promise.map(models, function(model) {
+      return model.truncate(options);
+    });
+  };
+
+  /**
    * Test the connection by trying to authenticate
    *
    * @fires success If authentication was successfull

test/integration/associations/has-many.test.js

@@ -896,7 +896,7 @@ describe(Support.getTestDialectTeaser('HasMany'), function() {
     describe('allows the user to provide an attribute definition object as foreignKey', function() {
       it('works with a column that hasnt been defined before', function() {
         var Task = this.sequelize.define('task', {})
-        , User = this.sequelize.define('user', {});
+          , User = this.sequelize.define('user', {});
 
         User.hasMany(Task, {
           foreignKey: {

test/integration/model.test.js

@@ -1130,6 +1130,22 @@ describe(Support.getTestDialectTeaser('Model'), function() {
   });
 
   describe('destroy', function() {
+    it('convenient method `truncate` should clear the table', function() {
+      var User = this.sequelize.define('User', { username: DataTypes.STRING }),
+          data = [
+            { username: 'user1' },
+            { username: 'user2' }
+          ];
+
+      return this.sequelize.sync({ force: true }).then(function() {
+        return User.bulkCreate(data);
+      }).then(function() {
+        return User.truncate();
+      }).then(function() {
+        return expect(User.findAll()).to.eventually.have.length(0);
+      });
+    });
+
     it('truncate should clear the table', function() {
       var User = this.sequelize.define('User', { username: DataTypes.STRING }),
           data = [
@@ -1155,7 +1171,7 @@ describe(Support.getTestDialectTeaser('Model'), function() {
         throw new Error('Destroy should throw an error if no where clause is given.');
       }, function(err) {
         expect(err).to.be.an.instanceof(Error);
-        expect(err.message).to.equal('Missing where or truncate attribute in the options parameter passed to destroy.');
+        expect(err.message).to.equal('Missing where or truncate attribute in the options parameter of model.destroy.');
       });
     });
 

test/integration/sequelize.test.js

@@ -647,8 +647,35 @@ describe(Support.getTestDialectTeaser('Sequelize'), function() {
     });
   });
 
+  describe('truncate', function() {
+    it("truncates all models", function() {
+      var Project = this.sequelize.define('project' + config.rand(), {
+            id: {
+              type: DataTypes.INTEGER,
+              primaryKey: true,
+              autoIncrement: true
+            },
+            title: DataTypes.STRING
+          });
+
+      return this.sequelize.sync({ force: true }).then(function() {
+        return Project.create({ title: 'bla' });
+      }).bind(this).then(function(project) {
+        expect(project).to.exist;
+        expect(project.title).to.equal('bla');
+        expect(project.id).to.equal(1);
+        return this.sequelize.truncate().then(function() {
+          return Project.findAll({});
+        });
+      }).then(function(projects) {
+        expect(projects).to.exist;
+        expect(projects).to.have.length(0);
+      });
+    });
+  });
+
   describe('sync', function() {
-    it('synchronizes all daos', function() {
+    it('synchronizes all models', function() {
       var Project = this.sequelize.define('project' + config.rand(), { title: DataTypes.STRING });
       var Task = this.sequelize.define('task' + config.rand(), { title: DataTypes.STRING });