目标

实时输入，实时更新，巩固 mutations 传参语法

实现步骤

---

代码示例

App.vue

<input :value="count" @input="handleInput" type="text">
<script>
    export default {
        methods: {
            handleInput (e) {
                // 1. 实时获取输入框的值
                const num = +e.target.value
                // 2. 提交mutation，调用mutation函数
                this.$store.commit('changeCount', num)
            }
        }
    }
</script>

store/index.js

mutations: { 
   changeCount (state, newCount) {
      state.count = newCount
   }
},