Working with maps in Typescript

I am having a bit of trouble working with maps int Typescript. What I am trying to do is to use a HashMap smilier to that found in Java for example here is my Java object,

public class Payment {
    private String id;
    private DateTime created;

    //when they actually received the payment
    private DateTime paidDate;
    private String customerId;
    private String companyId;
    private BigDecimal amount;
    private BigDecimal allocated;
    private String description;

    // it must be the Id of PaymentMethod
    private String type;

    //to improve it
    private String currency;

    private Boolean fullPaid = false;
    private Boolean lockArchive = false;

    //<InvoiceId, Amount>
    private HashMap<String, BigDecimal> invoices = new HashMap<>();

    //getter and setters....

So what I have done in Typescript it to create a similar class for example,

export class Payment {
  public id?:string;
  public created?:string;
  public paid_date?:Date;
  public customer_id?:string;
  public company_id?:string;
  public amount?:number;
  public allocated?:number;
  public description?:string;
  public type?:string;
  public currency?:string;
  public full_paid?:boolean;
  public lock_archive?:boolean;
  public invoices:  {[invoice_id:string]:number};


  constructor(id: string, created: string, paid_date: Date, customer_id: string, company_id: string, amount: number, allocated: number, description: string, type: string, currency: string, full_paid: boolean, lock_archive: boolean, invoices: { [p: string]: number }) {
    this.id = id;
    this.created = created;
    this.paid_date = paid_date;
    this.customer_id = customer_id;
    this.company_id = company_id;
    this.amount = amount;
    this.allocated = allocated;
    this.description = description;
    this.type = type;
    this.currency = currency;
    this.full_paid = full_paid;
    this.lock_archive = lock_archive;
    this.invoices = invoices;
  }
}

I am trying to to basically add to the the invoices map so I have the following function,

  public invoicesMap = new Map<string, number>();

  constructor(public dialogRef: MdDialogRef<PaymentInvoiceSelectDialogComponent>,
              private customerService:CustomerService,
              private paymentServices: PaymentsService) {

  }

  ngOnInit() {

    this.customer.subscribe((res)=>{
      this.customer_name = res.customer_name
    }, error=>{
      console.error(<any>error);
    });

    this.customerService.getListOfCustomerInvoices(this.customerId,'0','25')
      .subscribe( (res) =>{
       this.invoices = res;
      },
      error => {
        console.error(<any>error);
      });

  }

  selectedInvoice(invoiceId: string, amount: number, event:any) {

    if(event.checked){

      if(!_.isEmpty(this.payment.invoices)){

        for(let [key, value] of this.invoicesMap) {

          if (key !== invoiceId) {

            this.invoicesMap.set(invoiceId, amount);

            for(let [key, vvalue] of this.invoicesMap) {

              if (key === invoiceId) {

                this.availableAllocation = this.availableAllocation - vvalue;

              }
            }
          }
        }
      } else {

        this.invoicesMap.set(invoiceId,amount);

        for(let [key, vvalue] of this.invoicesMap) {
          if(key === invoiceId){
            this.availableAllocation = this.amount - vvalue;
          }
        }
      }
    } else if(!event.checked){

      for(let [key, vvalue] of this.invoicesMap) {

        if (key === invoiceId) {

          console.log("removing an item");
          this.availableAllocation += vvalue;
        }

      }
    }

    //at this point I would like to set this.payment.invoices to this.invoiceMap
    for(let [key, value] of this.invoicesMap){
      let v = {invoice_id:key,amount:value};
      console.log(v);
    }

    this.payment.allocated = this.availableAllocation;
  }


  savePayment(){
    console.log(JSON.stringify(this.payment));
    // this.paymentServices.updatePayment(this.payment)
    //   .subscribe((res)=>{
    //     this.payment = res;
    //     this.dialogRef.close(this.payment);
    //     },
    //     error =>{
    //       console.log(<any>error);
    //     });
  }

the items are added to the invoiceMap but the problem I am having now is adding invoiceMap to payment.invoices. If someone can point me in the right direction that would be much appreciated. Thanks