Property 'myForm' does not exist on type 'ShoppingCartComponent'

Question

I have the following component html:

<form *ngFor="let product of products" [formGroup]="myForm" name="myForm" (ngSubmit)="onSubmit([product.name], [product.price], int)">
<div id="cartItemsList">
<ul>
<li>
<div name="product_name">{{product.name }}</div>
<div><img src="../assets/images/gallery/{{product.thumbnail}}" /></div>
<div>{{product.price }}</div>
<button class="minus-btn" (click)="minus()" type="button" name="minus_btn">
<img src="../assets/images/minus.svg" alt="minus" /></button>
<input pattern="^(0|\+?[1-9]\d*)$" class="num" name="int" [value]="int" formControlName="int" ng-minlength="0" type="number">
<button class="plus-btn" (click)="plus()" type="button" name="plus_btn">
<img src="../assets/images/plus.svg" alt="plus" /></button>
<button type="submit" class="btnAddAction">Add to Cart</button>
</li>
</ul>
</div>
</form>

And in the controller ts file, I have:

ngOnInit(): void {
this.myForm = new FormGroup({
int: new FormControl()
});
}

I get the following error:

ERROR in src/app/shopping-cart/shopping-cart.component.ts:80:9 - error TS2339: Property 'myForm' does not exist on type 'ShoppingCartComponent'.

80 this.myForm = new FormGroup({

but as you can see, myForm does exist in the component. How can I fix this error?