Vue watch

<div id="app1">
    x : <input type='number' v-model="x" /><br />
    y : <input type='number' v-model="y" /><br /> <br>

    연산된 덧셈 결과 : 
</div>

<script type="text/javascript">
    var vm = new Vue({
        el: "#app1",
        data: {
            x: 0,
            y: 0,
            sum: 0
        },
        watch: {
            x: function (v) {
                if (v == "")
                    this.x = 0;
                this.sum = parseInt(this.y) + parseInt(this.x);
            },
            y: function (v) {
                if (v == "")
                    this.y = 0;
                this.sum = parseInt(this.y) + parseInt(this.x);
            }
        }
    })
</script>