title: Angular ReactiveForms not getting dynamic value
body: <p>I'm using reactive forms in Angular and i have this FormArray from which i am getting all value except <code>product_total</code>. </p>
  
  <pre><code>&lt;tbody formArrayName="products"&gt;
    &lt;tr *ngFor="let phone of productForms.controls; let i=index" [formGroupName]="i"&gt;
        &lt;th scope="row"&gt;{{i+1}}&lt;/th&gt;
        &lt;td&gt;&lt;input type="text" class="form-control" placeholder="Product Code" formControlName="product_code"&gt;&lt;/td&gt;
        &lt;td&gt;&lt;input type="text" class="form-control" placeholder="Product Name" formControlName="product_name"&gt;&lt;/td&gt;
        &lt;td&gt;&lt;input type="number" class="form-control" placeholder="Price" formControlName="product_price" #price&gt;&lt;/td&gt;
        &lt;td&gt;&lt;input type="number" class="form-control"  formControlName="product_quantity" value="1" #quantity&gt;&lt;/td&gt;
        &lt;td&gt;&lt;input type="number" class="form-control" value="{{(price.value || 0) * (quantity.value || 1)}}" formControlName="product_total" disabled&gt;&lt;/td&gt;
      &lt;/tr&gt;
    &lt;/tbody&gt;
  </code></pre>
  
  <p>How to get <code>product_total</code> value for each formgroup inside the typescript code?
  P.S. I'm getting the value inside the HTML Code but not in the typescript code</p>
  
  <p>The typescript code is:</p>
  
  <pre><code>constructor(private fb: FormBuilder) { }
  
  ngOnInit() {
  const product = this.fb.group({
    product_code: [],
    product_name: [],
    product_price: [],
    product_quantity: [1],
    product_total: []
  });
  
  this.myForm = this.fb.group({
    customer_name: '',
    customer_phone: '',
    customer_address: '',
    products: this.fb.array([product]),
    subtotal: Number,
    discount: Number,
    cgst: Number,
    sgst: Number,
    total_price: Number,
  });
  }
  
  get productForms() {
    return this.myForm.get('products') as FormArray;
  }
  
  
  async submitForm() {
      const myForm = this.myForm.value;
      this.invoice = {
        products: myForm.products,
      };
      console.log(this.invoice.products);
  
    }
  </code></pre>