Vue 3 get value from function @click event to use to calculate some math.

I'm making a tip calculator using vuejs 3 and typescript. I have 5 buttons with some values, I want to use their values to calculate a total, how do call the function tipPercentage so that it gives me a single numerical value which I can use to calculate the total, and also I can't add bill since it's a Ref type and not a number type. I'm using vue 3.2 script setup and typescript, open to javascript solution image of tip calculator app

<script lang="ts" setup>
import {ref} from 'vue'
let tips = [
  { id: 1, percent: 5},
  { id: 2, percent: 10},
  { id: 3, percent: 15},
  { id: 4, percent: 25},
  { id: 5, percent: 50},
]
 const bill: number  = ref(0)
let  tipPercentageValue = (percentValue: number) => percentValue
const total: number = bill  bill*tipPercentageValue(percentValue)
</script>

<h3>Bill</h3>
   <input  type="number" v-model="bill" placeholder="enter bill" />
    <h3>Select Tip %</h3>
        <div  >
          <button   v-for="tip in tips" :key="tip.id" @click="tipPercentageValue(tip.percent)" :value="tip.percent">
            {{ tip.percent }}%
          </button>
 </template>

CodePudding user response：

You have some problems in your code with the usage of ref. If you use the ref in your <script> and you want to assign a new value you need to add .value https://v3.vuejs.org/guide/reactivity-fundamentals.html#creating-standalone-reactive-values-as-refs

Furthermore your tipPercantageValuefunction does nothing.

  const selectedPercentage = ref(0)
  const total = ref(0)

  function percentageSelected(percentage: number) {
    selectedPercentage.value = percentage
    total.value = bill.value  bill.value*selectedPercentage.value
  }

like this total and billare reactive. Then use the percentageSelectedfunction as the @clickfunction

if you want the percentage to be in the 'correct' format add const computedPercantage = computed(() => selectedPercentage.value/100) and use it like

function percentageSelected(percentage: number) {
    selectedPercentage.value = percentage
    total.value = bill.value  bill.value*computedPercantage.value
  }