i've a vue apps containing datepicker by ant-design-vue that return

Moment {…}

_d: Thu Oct 24 1996 00:00:00 GMT+0800 (Malaysia Time)

_f: YYYY-MM-DD

_i: 1996-10-15

_isAMomentObject: (...)

_isUTC: (...)

_isValid: (...)

_locale: (...)

_pf: (...)

__ob__: Observer {value: Moment, dep: Dep, vmCount: 0}

get _d: ƒ reactiveGetter()

set _d: ƒ reactiveSetter(newVal)

get _f: ƒ reactiveGetter()

set _f: ƒ reactiveSetter(newVal)

get _i: ƒ reactiveGetter()

set _i: ƒ reactiveSetter(newVal)

get _isAMomentObject: ƒ reactiveGetter()

set _isAMomentObject: ƒ reactiveSetter(newVal)

get _isUTC: ƒ reactiveGetter()

set _isUTC: ƒ reactiveSetter(newVal)

get _isValid: ƒ reactiveGetter()

set _isValid: ƒ reactiveSetter(newVal)

get _locale: ƒ reactiveGetter()

set _locale: ƒ reactiveSetter(newVal)

get _pf: ƒ reactiveGetter()

set _pf: ƒ reactiveSetter(newVal)

__proto__: Object

where i need the date format in YYYY-MM-DD

it's succeed when get straight from onChange event with this code.

function(date = moment, dateString) {

      if (date) {

        console.log(dateString)

}

but in my project, i'm using v-decorator where gets all data through the form.
this is my script where i've tried calling the date:

this.form.validateFields((error, values) => {

          console.log(values.birthday);

)}

this is my datepicker structure:

<a-form-item v-bind=formItemLayout label=Date Of Birth>

    <a-date-picker

     v-decorator=[ 'birthday',

      {

       initialValue: moment(profile.birthday),

        rules: [{required: true, message: 'Date Of Birth is required.'}]

      },

     ]

       @change=handleAge

       format=DD/MM/YYYY

      style=width:120px;

      />

     </a-form-item>

and it's return the above moment. how can i get only YYYY-MM-DD format?