import { NativeStorage } from '@awesome-cordova-plugins/native-storage/ngx';
constructor(private nativeStorage: NativeStorage) { }
...
this.nativeStorage.setItem('myitem', {property: 'value', anotherProperty: 'anotherValue'})
  .then(
    () => console.log('Stored item!'),
    error => console.error('Error storing item', error)
  );
this.nativeStorage.getItem('myitem')
  .then(
    data => console.log(data),
    error => console.error(error)
  );