stroageState Vue 缓存hook

<template>
  <div class="home">

    <div>
      <Card style='margin: 20% auto; width: 600px' title=''>

        <p> {{ userInfo }} </p>
        <Input v-model="userName" />
        <Button @click='updateUserName' > update </Button>
        <Button @click='clearUserInfo' > clear </Button>
        <Button @click='addPrefix' > addPrefix </Button>
   
      </Card>
    </div>
    
  </div>
</template>

<script>
import { ref } from '@vue/composition-api'
import strongeStateHook from '@/hooks/strongeStateHook'


export default { 

  setup(){

    const [ userInfo, updateState ] = strongeStateHook(localStorage, 'USER_INFO', { name: 'coco' })
    const userName = ref('')
    const updateUserName = () => updateState({ ...userInfo.value, name: userName.value })
    const clearUserInfo = () => updateState()
    const addPrefix = () => updateState(userInfo => { return { name: `super-${userInfo.name}` } })

    return {
      userName,
      userInfo,
      updateUserName,
      clearUserInfo,
      addPrefix
    }
    

  }

}
</script>

import { ref } from '@vue/composition-api'

function isFunction(obj){
    return typeof obj === 'function'
}

function getStoreValue(storage, key, defaultValue){

    const raw = storage.getItem(key)

    if(raw){
        return JSON.parse(raw)
    }

    if(isFunction(storage)){
        return defaultValue()
    }
    
    return defaultValue
}


/**
 * 
 * @param { localStorage | sessionStorage } storage  
 * @param { string } key 缓存字段名 
 * @param { any } defaultValue 默认数据
 * @returns { array } [ state, updateState ] 返回缓存ref对象，及更新方法。 更新数据为空时，清楚缓存字段 
 * @summary 缓存基础函数，封装解析及格式化操作
 * @example
 *  
 * const [ userInfo, updateState ] = strongeStateHook(localStorage, 'USER_INFO', { nickname: 'coco', age: 24 })
 *  
 * const closeUserInfo = () => updateState()
 * const updateNickname = name => updateState({ ...userInfo.value, nickname: name }) 
 * 
 */
export default function stroageState(storage, key, defaultValue){

    const state = ref( getStoreValue(storage, key, defaultValue) )
    
    function updateState(value){

        if(typeof value === 'undefined'){
            storage.removeItem(key)
            state.value = undefined
            return 
        }

        if(isFunction(value)){
            const previousState = getStoreValue(storage, key, defaultValue)
            const currentState = value(previousState)
            storage.setItem(key, JSON.stringify(currentState))
            state.value = currentState
            return 
        }

        storage.setItem(key, JSON.stringify(value))
        state.value = value
    }

    return [ state, updateState ]
    
}