使Ember函数从回调返回承诺

Question

I want to have a function return the promise from model.save() , but the call to model.save() is in a callback, and so doesn't make it up the chain. Here's what I mean:

function saveOn (target, attribute) {
    target.addObserver(attribute, function () {
        if (target.get(attribute)) {
            target.removeObserver(attribute);
            Ember.run.once(target, function() {
                target.save();
            });
        }
    });
};

(this function was necessary to solve this problem I previously posted )

I want the target.save(); line to instead be: return target.save();

Then I could do this:

saveOn().then();

which as it stands doesn't work, the error message simply being that then doesn't exist on that object.

Update

teacherSignUp: function() {
    var model = this.get('model');
    var teacher = this.get('store').createRecord('teacher', {
        description: 'Why hello sir',
        user: model
    });
    model.set('teacher', teacher);
    saveOn(teacher, 'user.isFulfilled').then(function() {
        console.log("Model");
        saveOn(model, 'teacher.isFulfilled');
    });
}

The console.log("Model"); is successfully called, but the model is never persisted at all. What's happening here?

Update Solved

It the second observer on the model was never firing, since after the teacher had completed saveOn the model was already done. I just changed the saveOn(model, 'teacher.isFulfilled'); to model.save(); and it works great.

Answer 1

pass another parameter.

function saveOn (target, attribute, then) {
    target.addObserver(attribute, function () {
        if (target.get(attribute)) {
            target.removeObserver(attribute);
            Ember.run.once(target, function() {
                var promise = target.save();
                if(then){ 
                  promise.then(function(){ then(); });
          });
        }
    });
};

or create another promise and resolve in the then

function saveOn (target, attribute) {
    return new Ember.RSVP.Promise(function(resolve, reject){

      target.addObserver(attribute, function () {
        if (target.get(attribute)) {
            target.removeObserver(attribute);
            Ember.run.once(target, function() {
                target.save().then(function(record){ resolve(record); },
                      function(error){ reject(error); });
          });
        }
      });
    });
};

teacher.isFulfilled is probably already changed, so the observer isn't firing, cause it isn't changing, try checking before creating the observer and skipping that portion if already true/exists etc.