vue.js set data in if statement of function

Question

I have a form that runs of Vue that looks like this:

new Vue({
            el: '#login-container',
            data: {
                firstname: '', 
                lastname: '', 
                email: '', 
                birthday: '', 
                signupEmail: '', 
                password: '', 
                signupPassword: '', 
                confirm: '',
                error: '',
            },
            methods: {

                login(){

                    CH.INSTANCE.Services.Login(this.email, this.password, login_onComplete, login_onCancel);

                    function login_onComplete(aUser)
                    {
                      window.location.href = '/';
                    }

                    function login_onCancel(aMessage)
                    {
                        this.error =  aMessage ;
                    }
                },

                signup(){

                      CH.INSTANCE.Services.CreateAccount(this.firstname,this.lastname,this.signupEmail, this.signupPassword,'83835', 'male',this.birthday,':checked',onRegister_onComplete,onRegister_onError);

                      function onRegister_onComplete(aUser)
                      {
                          window.location.href = '/';
                      }

                      function onRegister_onError(aMessage)
                      {
                          this.error = aMessage;
                      }
                }

            }
        })

It works fine minus the the this.error = aMessage ; .

aMessage will contain the error message that should be dumped in {{error}} on my form if something goes wrong. The issue is it does get set.

If I set this.error = 'test' ; outside the if at the beginning of the login() method with works when its called.

If I just do console.log(aMessage) in the if that works as well.

Not sure why it does work when its set.

Answer 1

The problem is that within those functions, this does not refer to your Vue instance. I would set up your functions like this:

login() {
  CH.INSTANCE.Services.Login(this.email, this.password, this.login_onComplete, this.login_onCancel);
},
login_onComplete(aUser) {
  window.location.href = '/';
},
login_onCancel(aMessage) {
  this.error =  aMessage ;
}