method to tell if a model needs saving

[calvinmetcalf]

as far as I can tell isDirty is the only way to tell if a model has been changed, but that does not get triggered if you change a belongsTo relationship, e.g.

//models/person.js
export default DS.Model.extend({
  employer: DS.belongsTo('company'),
  largeData: DS.attr()
});

// somewhere else

person.set('employer', somethingElse);
person.get('isDirty');//false

I ended up having to write this

function actuallyDirty(model) {
    if (model.get('isDirty')) {
      return true;
    }
    var state = false;
    model.eachRelationship(function (rel) {
      if ((model._data[rel] && model._data[rel].id) !== model.get(rel + '.id')) {
        state = true;
      }
    });
    return state;
  }

[nwjsmith]

I believe this is a dup of #1367

[calvinmetcalf]

the ask here is for a way to tell if it's been changed, not necessarily having isDirty apply to relationships.

[DougPuchalski]

+1 I'm noticing also that rollback doesn't reset a belongsTo back to the persisted value (as it's not added to _inFlightAttributes).

[knownasilya]

areRelationshipsDirty and another one that is dirtyRelationships which returns an array of dirty relationships, either strings or the actual objects. Probably strings, attribute names.

[timrwood]

I've opened an RFC for this issue. Please weigh in.

emberjs/rfcs#21

[igorT]

Tracking this under #2122