Strict done!!

overlord/src/app/purchases/purchases-item.ts

@@ -4,4 +4,13 @@ export class PurchasesItem {
   rate: number;
   amount: number;
   url: string[];
+
+  public constructor(init?: Partial<PurchasesItem>) {
+    this.name = '';
+    this.quantity = 0;
+    this.rate = 0;
+    this.amount = 0;
+    this.url = [];
+    Object.assign(this, init);
+  }
 }

overlord/src/app/purchases/purchases.component.ts

@@ -17,10 +17,10 @@ import { PurchasesItem } from './purchases-item';
 export class PurchasesComponent implements OnInit {
   @ViewChild(MatPaginator, { static: true }) paginator?: MatPaginator;
   @ViewChild(MatSort, { static: true }) sort?: MatSort;
-  dataSource: PurchasesDataSource;
+  info: Purchases = new Purchases();
+  dataSource: PurchasesDataSource = new PurchasesDataSource(this.info.body);
   form: FormGroup;
-  info: Purchases;
-  selectedRowId: string;
+  selectedRowId = '';
   /** Columns displayed in the table. Columns IDs can be added, removed, or reordered. */
   displayedColumns = ['product', 'quantity', 'rate', 'amount'];
 
@@ -40,7 +40,7 @@ export class PurchasesComponent implements OnInit {
         startDate: moment(this.info.startDate, 'DD-MMM-YYYY').toDate(),
         finishDate: moment(this.info.finishDate, 'DD-MMM-YYYY').toDate(),
       });
-      this.dataSource = new PurchasesDataSource(this.paginator, this.sort, this.info.body);
+      this.dataSource = new PurchasesDataSource(this.info.body, this.paginator, this.sort);
     });
   }
 

overlord/src/app/purchases/purchases.service.ts

@@ -16,7 +16,7 @@ const serviceName = 'PurchasesService';
 export class PurchasesService {
   constructor(private http: HttpClient, private log: ErrorLoggerService) {}
 
-  list(startDate: string, finishDate): Observable<Purchases> {
+  list(startDate: string | null, finishDate: string | null): Observable<Purchases> {
     const startDateWithSlash = startDate ? `/${startDate}` : '';
     const finishDateWithSlash = finishDate ? `/${finishDate}` : '';
     return <Observable<Purchases>>(

overlord/src/app/purchases/purchases.ts

@@ -5,4 +5,12 @@ export class Purchases {
   finishDate: string;
   body: PurchasesItem[];
   footer: PurchasesItem;
+
+  public constructor(init?: Partial<Purchases>) {
+    this.startDate = '';
+    this.finishDate = '';
+    this.body = [];
+    this.footer = new PurchasesItem();
+    Object.assign(this, init);
+  }
 }