Updated to angular 11

Now compiling with strict mode in typescript
Need to error checking now

bookie/src/app/core/section-printer.ts

@@ -5,4 +5,11 @@ export class SectionPrinter {
   menuCategory: MenuCategory;
   printer: Printer;
   copies: number;
+
+  public constructor(init?: Partial<SectionPrinter>) {
+    this.menuCategory = new MenuCategory();
+    this.printer = new Printer();
+    this.copies = 0;
+    Object.assign(this, init);
+  }
 }