RandomBook.addCategoryField

<div class="book-form-categories" formArrayName="bookCategories"
            *ngFor="let item of addBookForm.get('bookCategories')['controls']; let i = index;">
            <mat-form-field [formGroupName]="i" class="book-form-category">
                <mat-label>Book Category</mat-label>
                <mat-select formControlName="bookCategory" required>
                    <mat-option *ngFor="let category of data" [value]="category.Name">
                        {{category.Name}}
                    </mat-option>
                </mat-select>
            </mat-form-field>
            <button *ngIf="i!=0" mat-button (click)="removeCategoryControl(i)">
                <mat-icon>delete</mat-icon>

            </button>

        </div>