Utils

Sequelize comes with some handy utils including references tolodashas well as some individual helpers. You can access them viaSequelize.Utils.

Lodash.js

You can access all the methods of lodash like this:

Sequelize.Utils._.each(/* ... */)
Sequelize.Utils._.map(/* ... */)
Sequelize.Utils._...

Also Sequelize ships the Underscore extensionunderscore.string, which allows nifty string manipulation:

Sequelize.Utils._.camelize('something') // Something

Check out the page of Lodash, Underscore and underscore.string for further information.

QueryChainer

Because you will want to save/create/delete several items at once and just go on after all of them are saved, Sequelize provides theQueryChainermodule. It can be used like this:

var chainer = new Sequelize.Utils.QueryChainer
chainer.add(/* Query | EventEmitter */)
chainer.run().success(function(){}).error(function(errors){})

And a real world example:

var chainer = new Sequelize.Utils.QueryChainer
var Task    = sequelize.define('Task', /* ... */)
 
chainer
  .add(Task.drop())
  .add(Task.sync())
 
for(var i = 0; i < 20; i++)
  chainer.add(Task.create({}))
 
chainer
  .run()
  .success(function(){})
  .error(function(errors){})

It is also possible to force a serial run of the query chainer by using the following syntax:

new Sequelize.Utils.QueryChainer()
  .add(Model, 'function', [param1, param2])
  .add(Model, 'function2', [param1, param2])
  .runSerially()
  .success(function() { /* no problems :) */ })
  .error(function(err) { /* hmm not good :> */ })
 
// and with options:
 
new Sequelize.Utils.QueryChainer()
  .add(Model, 'function', [param1, param2], {
    // Will be executed before Model#function is called
    before: function(model) {},
 
    /*
      Will be executed after Model#function was called
      and the function emitted a success or error event.
      If the following success option is passed, the function
      will be executed after the success function.
    */
    after: function(migration) {},
 
    // Will be executed if Model#function emits a success event.
    success: function(migration, callback) {}
  })
  // skipOnError: don't execute functions once one has emitted an failure event.
  .runSerially({ skipOnError: true })
  .success(function() { /* no problems :) */ })
  .error(function(err) { /* hmm not good :> */ })

If the success callbacks of the added methods are passing values, they can be utilized in the actualsuccessmethod of the query chainer:

chainer.add(Project.getTasks())
chainer.add(Project.getTeam())
chainer.run().success(function(results){
  var tasks = results[0]
  var team = results[1]
})