<template>
  <div>
    <h1>当前求和为: {{sum}}</h1>
    <select v-model.number="n">
      <option value="1">1</option>
      <option value="2">2</option>
      <option value="3">3</option>
    </select>
    <button @click="add">+</button>
    <button @click="sub">-</button>
    <button @click="addOdd">当前求和为奇数再加</button>
    <button @click="addWait">等一等再加</button>
  </div>
</template>

<script>
export default {
  name: "Count",
  data() {
    return {
      n: 1,
      sum: 0
    }
  },
  mounted() {
    console.log('Count', this)
  },
  methods: {
    add() {
      this.sum += this.n
    },
    sub() {
      this.sum -= this.n
    },
    addOdd() {
      if (this.sum % 2) {
        this.sum += this.n
      }
    },
    addWait() {
      setTimeout(()=>{
        this.sum += this.n
      }, 500)
    }

  }
}
</script>

<style>
button {margin-left: 5px}
</style>