Previous Attributes after save() call

[jgable]

I'm trying to get the previous attributes after calling save() and having a hard time. Something like this is what I'd expect:

describe('previous, previousAttributes', function() {

  it('will return the previous value of an attribute the last time it was synced', function() {
    var model = new Models.Site({id: 1});
    return model.fetch().then(function() {
      return model.save({
        name: 'updatedknexjs.org'
      });
    })
    .then(function (u) {
      equal(model.get('name'), 'updatedknexjs.org');

      // This fails
      equal(model.previous('name'), 'knexjs.org');

      model.set('name', 'knexjs.org');

      return model.save();
    });

  });

});

Is there some other mechanism I can check after a save() call to get what attributes changed?

[tgriesser]

Hmm, I don't know, I guess it depends on how you're trying to use "previous"... presumably you could do this:

var previous;
var model = new Models.Site({id: 1});
    return model.fetch().then(function() {
      previous = this.get('name')
      return model.save({
        name: 'updatedknexjs.org'
      });
    })
    .then(function (u) {
      equal(previous, 'knexjs.org');
      equal(model.get('name'), 'updatedknexjs.org');
      model.set('name', 'knexjs.org');
      return model.save();
    });

or this:

var previousAttrs;
var model = new Models.Site({id: 1});
    return model.fetch().then(function() {
      model.set(someValues)
      previousAttrs = this.previousAttributes();
      return model.save();
    })
    .then(function (u) {
      // compare previousAttrs here
      equal(model.get('name'), 'updatedknexjs.org');
      return model.save();
    });

would either of these work?

[jgable]

The use case is for TryGhost/Ghost#1563, we need to try and detect when a Post's status is changed from draft to published in order to set a X-Cache-Invalidate header on the request.

I'm thinking of listening to the saving and saved listeners and just assigning a this.updatedAttributes or something for comparing.

I'll try to report back if that works.

[tgriesser]

In the saved event, it puts the previousAttributes on the options object incase you need them for something like this: link

[jgable]

I ended up adding the following to our base models and it seems to provide the functionality I'm looking for:

saving: function (newObj, attr, options) {
    // Store the previous attributes so we can tell what was updated later
    this._updatedAttributes = newObj.previousAttributes();
},

// Get attributes that have been updated (values before a .save() call)
updatedAttributes: function () {
    return this._updatedAttributes || {};
},

// Get a specific updated attribute value
updated: function (attr) {
    return this.updatedAttributes()[attr];
}

I couldn't get the options.previousAttributes to work for me, but this approach seems to be working.

[tgriesser]

Cool.

[gaastonsr]

This is a bug right? I'm having the same problem, I do:

/* user has "jdoe" as nickname */

user.save({
    nickname: 'updated'
})
.then(function(model) {
    console.log(model.previous('nickname'));
});

And I get "updated", is not supposed to return "jdoe"?

[thetutlage]

Not working , i have tried using all the hooks , saving ,saved , updating , updated and previousAttributes are blank in every case

[gaastonsr]

Do you have a test case so we can help you?

[thetutlage]

Yes

UserModel

bookshelf.model("Users",{
   initialize: function(){
        this.on("creating", this._beforeCreate, this);
        this.on("created", this._afterCreate, this);
        this.on("updating", this._beforeUpdate, this);
        this.on("updated", this._afterUpdate, this);
   },
   _beforeUpdate: function(model,attrs,options){
       console.log('model>>>>>',model);
       console.log('options>>>>>',options);
   },
   _afterUpdate: function(model,response,options){
       console.log('after:model>>>>>',model);
       console.log('after:options>>>>>',options);
   }
});

Now i will paste the console output from my unit tests

After update

Before update

Old email in my database was user@example.com which i updated with new@example.com

Update Query

      var data_object = {email_address:'new@example.com',email_verified:false};
      return self.model.forge({id:user_id})
      .save(data_object,{patch: true});

Here self.model is something inside collection

[gaastonsr]

I confirmed a while back that previousAttributes has a bug. I don't know if that claim is still valid. I would recommend you to workaround the problem by saving your attributes before your actions and make use of them later as it they were extracted from previous attributes.

var previousAttributes = model.toJSON();

// your actions
model.update();

// and later use them
console.log(previousAttributes.email); // old email!

[awHamer]

+1 After model is saved I'm expecting that previous attributes would be exactly previous attributes, but I got the same data that I set in update request

[aef-]

Can this be opened as a bug? I'm experiencing this in 0.8.2.

[rhys-vdw]

@aef- There's a lot going on here, could you open a new issue showing exact use case with expected and actual ouput.