JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdn.jsdelivr.net/npm/vue"></script>
<div id="app">
  <ul>
    <li v-for="item in list">
      <p>{{item.goods_name}}</p>
      <p>{{item.goods_price}}</p>
      <a v-show="item.count > 0" @click.stop.prevent="lessCart(item,$event)">-</a>
      <input v-show="item.count > 0" v-model="item.count">
      <a @click.stop.prevent="addCart(item,$event)">+</a>
    </li>
  </ul>
</div>

JavaScript

const goods = [{
  id: "1",
  goods_name: "a",
  goods_price: "30.00",
  goods_num: "15",
  count:"0"
}, {
  id: "2",
  goods_name: "b",
  goods_price: "28.00",
  goods_num: "10",
  count:"0"
}]

var app = new Vue({
  el: "#app",
  data: {
    list: goods,
  },
  methods: {
  addCart(item,event) {
        if (!this.item.count) {
          Vue.set(this.item, 'count', 1);
        } else {
          this.item.count++;
        }
      },
    lessCart(event) {
        this.item.count--;
      }
     
  }

})