Mat-Dialog Using In Memory Service Angular

So, I'm creating a user dialog that will fill a FormArray. Depending on the number assigned to it, it will populate a row. My problem is: how do you save temporary the data that they filled up? Is there any alternative beside in memory for saving temporary data?

ngOnInit(): void {
    this.serialForm = this.fb.group({
      id: [0],
      deliveryReceiptDetailsId:[0],
      itemCode:['', Validators.required],
      qtyReceived:[0, Validators.required],
      inputs: this.fb.array([this.CreateArray()]),
    });
    this.serialForm.get('qtyReceived').valueChanges.subscribe((res) => {
      for (let i = this.displayArray.length; i < res; i++) {
        this.displayArray.push(this.CreateArray());
        console.log(this.displayArray);
      }
    });
    this.dataValues = this.serialForm.get('id').setValue(this.data.id),
    this.dataValues = this.serialForm.get('qtyReceived').setValue(this.data.qtyReceived),
    this.dataValues = this.serialForm.get('itemCode').setValue(this.data.propertyNo)
  

  }

  get displayArray():FormArray{
    return this.serialForm.get('inputs') as FormArray;
  }
  CreateArray():FormGroup{
    return new FormGroup({
      serialNum: new FormControl('', {validators: [Validators.required]}),
    });
  }

This is my service, where I tried to post it in memory:

@Injectable({
  providedIn: 'root'
})
export class SerialCodeService {
  private url = 'api/serial';
  private headers = new HttpHeaders({ 'Content-Type': 'application/json' });
  constructor(private http: HttpClient) { }

  getHeroes (data:any): Observable<any> {
    return this.http.post(this.url, data);
}
  }

Here's where I tried to store the sample data:

Injectable({
  providedIn: 'root'
})
export class InMemoryDataService implements InMemoryDbService {

  createDb() {
    const serial = [
      
      {id: 1, deliveryReceiptDetailsId: 0, itemCode:'sample1', qtyReceived:0 ,serialNum:"" },
      {id: 2, deliveryReceiptDetailsId: 0, itemCode:'sample2', qtyReceived:0 ,serialNum:"" },
      {id: 3, deliveryReceiptDetailsId: 0, itemCode:'sample3', qtyReceived:0  ,serialNum:""},
    ];
    return {serial};
  }
  genId(SerialBarCode: SerialCodeDTO[]): number{
    return SerialBarCode.length > 0
    ? Math.max(...SerialBarCode.map(serial => serial.id)) + 1
    : 1;
  }
}