Avoid mutating a prop directly since the value will be overwritten

Question

I have very common problem with upgrading to Vue 2.0

I am getting warning:

Avoid mutating a prop directly since the value will be overwritte

Answer 1

var GuestMenu = Vue.extend({
   props : {
    uNpW:{type:Object}
   }
      template: `
        

            

                

                    User name
                  
                
                

                  Password
                  
                
            
        
`,
    });

App = new Vue ({ 
   el: '#app',
  data: 
    {
      topMenuView: "guestmenu",
      contentView: "guestcontent",
      unAndPw:{username: "",password: ""}

    }
})

in main html
 

you dont need emit or any other thing