Data item array duplicated in app when add or delete from data from firebase

[murtadaalwaely]

"angularfire2": "^5.0.2",
"firebase": "^5.5.5",
"ionic-angular": "3.9.2",
"angular/compiler": "5.2.11",,
"angular/fire": "^5.0.2",

I am using angularfire2 with ionic3 to send and get data realtime from firebase.
I have used this command to install it and it worked
npm install firebase @angular/fire --save

retrieve data is working by using this code

this.categorieslistitems= this.db.list('/categories', ref => ref.orderByChild('title')); this.categorieslistitems.snapshotChanges().subscribe(actions => { actions.forEach(action=>{ let ky = action.payload.toJSON() ky['key'] = action.key this.categoriesitemArray.push(ky as postdata1)})})
`
export interface postdata1 {

key?: string;
title:string;
img:string;

}
`
using open firebase security rules

now I am getting data from firebase correctly ,
but when I add or delete data from firebase ,my item array or my list getting duplicated in the app only ,and its not duplicated in the database ,when i refresh the app its return normal

adding only the last data have inserted to firebase in realtime

data getting duplicated in app only with adding the new recorded with the duplicated record

[alberthoekstra]

Where do you clear the this.categoriesitemArray ?

Why don’t you use the observable?

[jamesdaniels]

Closing as outdated.