Vue JS focus next input on enter

After some tests, it's working

new Vue({
    el:'#app',
    methods: {
      nextPlease: function (event) {
        document.getElementById('input2').focus();
      }
    }
});

<script src="https://vuejs.org/js/vue.js"></script>
<div id='app'>
    <input type="text" v-on:keyup.enter="nextPlease">
    <input id="input2" type="text">
</div>

directives: {
    focusNextOnEnter: {
        inserted: function (el,binding,vnode) {
            let length = vnode.elm.length;
            vnode.elm[0].focus();
            let index = 0;
            el.addEventListener("keyup",(ev) => {
                if (ev.keyCode === 13 && index<length-1) {
                  index++;
                  vnode.elm[index].focus();
                }
            });
            for (let i = 0;i<length-1;i++) {
                vnode.elm[i].onfocus = (function(i) {
                  return function () {
                    index = i;
                  }
                })(i);
            }
        }
    }
}

// use it

<el-form v-focusNextOnEnter>
...
</el-form>

Following up from @zurzui here is in my opinion a cleaner alternative using the $refs API (https://v2.vuejs.org/v2/api/#vm-refs).

Using the $refs API, can allow you to target element in a simpler fashion without traversing the DOM.

Example: https://jsfiddle.net/xjdujke7/1/

You can try something like this:

<input v-on:keyup.enter="$event.target.nextElementSibling.focus()" type="text">

JSfiddle Example

Update

In case if the target element is inside form element and next form element is not a real sibling then you can do the following:

html

<form id="app">
  <p>{{ message }}</p>

  <input v-on:keyup.enter="goNext($event.target)" type="text">
  
  <div>
      <input type="text">
  </div>

</form>

js

new Vue({
  el: '#app',
  data: {
    message: 'Hello Vue.js!',
    focusNext(elem) {
      const currentIndex = Array.from(elem.form.elements).indexOf(elem);
      elem.form.elements.item(
        currentIndex < elem.form.elements.length - 1 ?
        currentIndex + 1 :
        0
      ).focus();
    }
  }
})

JSFiddle Example