store.js:

store = new Vuex.store({
    state:{
      inputVal: ''
    },
    mutations:{
      setInput (state, newVal) {
        state.inputVal = newVal
      }
    } }) 

页面中绑定：

<template>
  <div>
    <input v-model = 'storeVal'>
  </div>
</template>
<script>
export default {
  computed: {
    storeVal (e) {
      get() {
        return this.$store.state.inputVal
      },
      set(newVal) {
        this.$store.commit('setInputVal', newVal)
     }
    }
  }
}
</script>