如何使用Vue.js对表单域的值求和？

data() {
  return {
    formValues: {
      value1: 0,
      value2: 0,
      value3: 0
    },
    sum: 0
  };
},

<input type="number" v-model="formValues.value1">
<input type="number" v-model="formValues.value2">
<input type="number" v-model="formValues.value3">

computed: {
  calculateSum() {
    let sum = 0;
    for (let key in this.formValues) {
      sum += parseInt(this.formValues[key]);
    }
    return sum;
  }
}

<p>Sum: {{ calculateSum }}</p>