item.toLowerCase is not a function

Ionic Framework ionic-v3
1

This is my code:
items:any[] = [];

 ngOnInit() {
    this.setItems();
  }

  setItems() {
    this.items;
  }

  filterItems(ev: any) {
    this.setItems();
    let val = ev.target.value;

      if (val && val.trim() !== '') {
      this.items = this.items.filter(function(item) {
        return item.toLowerCase().includes(val.toLowerCase());
      });
    }
  }

i’m array push from here:

ionViewDidLoad() {
   var headers = new Headers();
    headers.append('Content-Type', 'application/x-www-form-urlencoded');
    let options = new RequestOptions({ headers: headers });

     this.http.get(myurl+"/leadlistingusers");
     
      .subscribe((res:Response)=>{
      let dataTemp = res.json(); //dataTemp is the json object you showed me
      this.mydata = dataTemp.viewleadusers; //contains a [] object with all yours user
       for(let i = 0; i < this.mydata.length; i++){
           
            let a = this.mydata[i].userName;
            let b= this.mydata[i].userID;
            alert(b);
            alert(a);
            this.items.push({
               "userID": b,
               "userName":a
            });
              
       }
  })
   
 };

How can i fix that.

2

items array contains objetcs not strings… try item.userName.toLowerCase()