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How to use js to protect variables from being modified at will

一个新手
Release: 2017-10-06 10:42:25
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/** 1.如果在renderTitle,renderContent里面,这样总数据谁都能修改,不安全
* 改进
* 1.规定一个专门修改数据的方法,如果想修改数据只能走这个方法
*
* action代表一个命令对象,就是一个普通的js对象,起码需要一个字段控制命令类型type,其他字段随意
*
* */const CHANGE_FONT_SILE='CHANGE_FONT_SILE';//设置一个闭包,把变量保护起来,通过返回值调用function createStore() {
    let appState={
        fontSize:'26px',
        title:{
            text:'标题',
            color:'red'
        },
        content:{
            text:'类容',
            color:'green'
        }
    }    //保护变量被修改,深克隆
    let getState=()=>JSON.parse(JSON.stringify(appState));    //改变变量的方法
    let dispatch=(action)=>{        
        switch(action.type){            
        case CHANGE_FONT_SILE:
                appState.fontSize=action.fontSize;            
                default:                
                return;
        }
    }    //返回出去的修改和取值的接口
  return{
      getState,
      dispatch
  }
}

let store=createStore();//取值函数function renderTitle() {
    let titleEle = document.querySelector('#title');

    titleEle.innerHTML = store.getState().title.text;
    titleEle.style.color = store.getState().title.color;
    titleEle.style.fontSize = store.getState().fontSize;
}function renderContent() {
    let titleEle=document.querySelector("#content");
    titleEle.innerHTML=store.getState().content.text;
    titleEle.style.color=store.getState().content.color;
    titleEle.style.fontSize=store.getState().fontSize;
}function renderApp() {
    renderTitle();
    renderContent()
}//修改appState里面初始值,单独一个修改文件store.dispatch({type:CHANGE_FONT_SILE,fontSize:'30px'})
renderApp();
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