动态生成的一组input,触发enter事件后怎么focus下一个input

<li class="border-none" v-for="(item,index) in prcHdAreaList" :key="item.pmcKeyVal">
    <input
         :ref="item.pmcKeyVal"
         v-focus-next-on-enter="'item.pmcKeyVal'" 
         name="item.phaRate" class="cus_input" 
         v-model.trim="item.phaRate" type="number"/>
</li>

Vue.directive('focusNextOnEnter', {
      bind: function(el, {value}, vnode) {
        el.addEventListener('keyup', (ev) => {
          if (ev.keyCode === 13) {
            let nextInput = vnode.context.$refs[value]
            if (nextInput && typeof nextInput.focus === 'function') {
              nextInput.focus()
              nextInput.select()
            }
          }
        })
     }
})