add merchant instance field at the right places

lib/wallet/types.ts

@@ -336,6 +336,30 @@ export interface WalletBalanceEntry {
 }
 
 
+interface Merchant {
+  /**
+   * label for a location with the business address of the merchant
+   */
+  address: string;
+
+  /**
+   * the merchant's legal name of business
+   */
+  name: string;
+
+  /**
+   * label for a location that denotes the jurisdiction for disputes.
+   * Some of the typical fields for a location (such as a street address) may be absent.
+   */
+  jurisdiction: string;
+
+  /**
+   * Instance of the merchant, in case one merchant
+   * represents multiple receivers.
+   */
+  instance?: string;
+}
+
 @Checkable.Class
 export class Contract {
   @Checkable.String

lib/wallet/wallet.ts

@@ -147,6 +147,11 @@ interface PayReq {
   timestamp: string;
   transaction_id: number;
   pay_deadline: string;
+  /**
+   * Merchant instance identifier that should receive the
+   * payment, if applicable.
+   */
+  instance?: string;
 }
 
 interface Transaction {
@@ -590,6 +595,7 @@ export class Wallet {
       pay_deadline: offer.contract.pay_deadline,
       timestamp: offer.contract.timestamp,
       transaction_id: offer.contract.transaction_id,
+      instance: offer.contract.merchant.instance
     };
     let t: Transaction = {
       contractHash: offer.H_contract,