如何使条件进入离子存储

Question

我正在开发运行在安卓手机上的Ionic2应用程序。它不需要远程数据库。所以我决定使用本地存储"商店"。

我找到了一些文章并做了一些改进，如下所示。我成功地获得了所有值，但我想在某些条件下获得一些东西，例如 SQL 中的"where"语句。(getWorksOn(someDate({...}(

我搜索并阅读了30多篇热门文章，但我找不到路。如果有办法，请告诉我。

// work-service.ts
addWork(work){
  this.storage.get('myWorks').then((data) => {
    if(data != null){
      data.push(work);
      this.storage.set('myWorks', data);
    } else {
      let tempWorks = [];
      tempWorks.push(work);
      this.storage.set('myWorks', tempWorks);
    }
  });
}
getWorks(){
  return this.storage.get('myWorks');
}
getWorksOn(someDate){
  // I want to return works that worked on someDate 
  // Is there any way to get some value conditionally 
  return this.storage.get('myWorks');
} 
// work-list.ts 
works:any;
...
ngOnInit(){
  this.workService.getWorks().then((data)=>{
    this.works = data;
  });
} 

Answer 1

如果您使用的是 Lodash，那么您可以如下所示进行操作。

注意：您无法在local storage内执行此操作。那你必须做这样的事情...

getWorksOn(someDate){
 this.storage.get('myWorks').then((val) => {
    let myworkArray = val; //firstly, fetched the data
    let myworkArray2= _.filter(myworkArray , { 'date': someDate});//after that filter out according to your condition
    });
}

OP使用map的反馈和filter array的功能

    this.workService.getWorks().then((works) => { this.works = works.filter(work 
=> work.dateStr === this.dateStr ); });