[рони]

fori,
или так локально

<script src="https://cdn.jsdelivr.net/npm/vue@2/dist/vue.js"></script>
<input id="vue" type="text" v-model="variable" v-my>
<script>
var vue = new Vue({
    el: '#vue',
    data: {
        variable: "",
    },
    directives: {
        my: {
            bind: function(el) {
                el.addEventListener('input', event => {
                    alert(el.value);
                }, true)
            }
        }
    }
})
</script>