Feature: Tax Regimes are added so that different bills with different series can be printed for Different regimes such as VAT and GST

Chore: Model relationships updated to make them simpler
Chore: Bill printing majorly refactored for it

Due to the sheer depth of the changes. There can be showstoppers. Please test it carefully

bookie/src/app/modifiers/modifier-detail/modifier-detail.component.ts

@@ -1,5 +1,5 @@
 import { AfterViewInit, Component, ElementRef, OnInit, ViewChild } from '@angular/core';
-import { UntypedFormBuilder, UntypedFormGroup } from '@angular/forms';
+import { FormControl, FormGroup } from '@angular/forms';
 import { MatDialog } from '@angular/material/dialog';
 import { ActivatedRoute, Router } from '@angular/router';
 
@@ -16,7 +16,14 @@ import { ModifierService } from '../modifier.service';
 })
 export class ModifierDetailComponent implements OnInit, AfterViewInit {
   @ViewChild('name', { static: true }) nameElement?: ElementRef;
-  form: UntypedFormGroup;
+  form: FormGroup<{
+    name: FormControl<string>;
+    showInBill: FormControl<boolean>;
+    price: FormControl<number>;
+    modifierCategory: FormControl<string>;
+    isActive: FormControl<boolean>;
+  }>;
+
   modifierCategories: ModifierCategory[] = [];
   item: Modifier = new Modifier();
 
@@ -24,17 +31,16 @@ export class ModifierDetailComponent implements OnInit, AfterViewInit {
     private route: ActivatedRoute,
     private router: Router,
     private dialog: MatDialog,
-    private fb: UntypedFormBuilder,
     private toaster: ToasterService,
     private ser: ModifierService,
   ) {
     // Create form
-    this.form = this.fb.group({
-      name: '',
-      showInBill: '',
-      price: '',
-      modifierCategory: '',
-      isActive: '',
+    this.form = new FormGroup({
+      name: new FormControl<string>('', { nonNullable: true }),
+      showInBill: new FormControl<boolean>(true, { nonNullable: true }),
+      price: new FormControl<number>(0, { nonNullable: true }),
+      modifierCategory: new FormControl<string>('', { nonNullable: true }),
+      isActive: new FormControl<boolean>(true, { nonNullable: true }),
     });
   }
 
@@ -49,9 +55,9 @@ export class ModifierDetailComponent implements OnInit, AfterViewInit {
   showItem(item: Modifier) {
     this.item = item;
     this.form.setValue({
-      name: this.item.name || '',
+      name: this.item.name ?? '',
       showInBill: this.item.showInBill,
-      price: this.item.price || '',
+      price: this.item.price ?? 0,
       isActive: this.item.isActive,
       modifierCategory: this.item.modifierCategory ? (this.item.modifierCategory.id as string) : '',
     });
@@ -104,10 +110,10 @@ export class ModifierDetailComponent implements OnInit, AfterViewInit {
 
   getItem(): Modifier {
     const formModel = this.form.value;
-    this.item.name = formModel.name;
-    this.item.showInBill = formModel.showInBill;
-    this.item.price = +formModel.price;
-    this.item.isActive = formModel.isActive;
+    this.item.name = formModel.name ?? '';
+    this.item.showInBill = formModel.showInBill ?? false;
+    this.item.price = formModel.price ?? 0;
+    this.item.isActive = formModel.isActive ?? true;
     this.item.modifierCategory = new ModifierCategory({ id: formModel.modifierCategory });
     return this.item;
   }