Ionic storage search bar filter works but while clearing the data gets erased

hello everyone ! am using storage to store my json files.

my .JSON file looks like this.

hymn.JSON :

  [{
    "songno": "1.",
    "title": "அகோர கஸ்தி பட்டோராய்"
   },

 {
    "songno": "2.",
    "title": "அஞ்சாதிரு, என் நெஞ்சமே"
 },
 {
    "songno": "3.",
    "title": "அதிகாலை இயேசு வந்து"
 },
 {
    "songno": "4.",
    "title": "அதிசயங்களை"
 },
 {
    "songno": "5.",
    "title": "அநாதியான கர்த்தரே"
 }
 ]

home.html :

 <ion-searchbar (ionInput)="getItems($event)" aria-placeholder="search"></ion-searchbar>

Home.TS :

 export class HomePage {
 items : any = [] ;
 key : string = "items";
  filterItems: any;


  constructor(public navCtrl: NavController,private storage: Storage,public http:HttpClient) {
    this.importJson();
     }
   
        importJson(){
         let data:Observable <any> = this.http.get('assets/json/hymn.JSON');

      data.subscribe(result =>{
      this.items = result;
      this.storage.set(this.key, JSON.stringify(this.items));
      this.storage.get(this.key).then((val) => {
      if(val!=null && val!= undefined){

      this.filterItems = this.items;
     }
     });
     });
     }
   intializeItems(){

  this.importJson();


 }


 getItems(ev) {
// Reset items back to all of the items
  this.intializeItems();

  var valu = ev.target.value;


  if (valu && valu.trim() != '') {
  this.items = this.items.filter((item) => {
    return (item.songno.toLowerCase().indexOf(valu.toLowerCase()) > -1) ||
     (item.title.toLowerCase().indexOf(valu.toLowerCase()) > -1);

  })

  }
 }

The problem is the filer works .
For Eg : If i type 23 in search bar ,the 23rd ID appears but when i clear the 23 back the whole list vanishes showing only the 23rd ID . Thanks guys. Hope i get a solution here for this