Angular2: add and submit a new formGroup name and values with model driven form

Question

Adding to a FormArray via input field

To add values, via a form input, to an existing array I can use (click)="addAddress()" in the html where addAddress is defined in the component.ts to update values in an array in the form AppComponent:

ngOnInit() {
        this.myForm = this._fb.group({
            name: ['', [Validators.required, Validators.minLength(5)]],
            addresses: this._fb.array([
                this.initAddress(),
            ])
        });
    }

    initAddress() {
        return this._fb.group({
            street: ['', Validators.required],
            postcode: ['']
        });
    }

    addAddress() {
        const control = <FormArray>this.myForm.controls['addresses'];
        control.push(this.initAddress());
    }

And back in the html ngFor is used to add a set of input fields each time the 'add' button is clicked":

<div formArrayName="addresses">
          <div *ngFor="let address of myForm.controls.addresses.controls; let i=index" >
              <span>Address {{i + 1}}</span>
            <div [formGroupName]="i">
                <input type="text" formControlName="street">
                <input type="text" formControlName="postcode">
            </div>
          </div>
        </div>

Like the full working example here: https://embed.plnkr.co/sUjE1ULYhfDHLNBw2sRv/1

Adding to form FormGroup via input field

I would like to understand how to add a completely new FormGroup via form input. So taking the case of the example above...

Rather than adding to an array of addresses:

{
  "name": "",
  "addresses": [
    {
      "street": "Baker Street",
      "postcode": "w2"
    },
    {
      "street": "Bond Street",
      "postcode": "w1"
    }
  ]
}

Each time an address is added a new FormGroup is created where the user adds the FormGroupName for each via form input. For example:

{  
   "name":"",
   "home":{  
      "street":"Baker Street",
      "postcode":"w2"
   },
   "work":{  
      "street":"Bond Street",
      "postcode":"w1"
   }
}

fivedoor fivedoor · Accepted Answer · 2016-09-21T10:42:32

Using the addControl method this can be achieved like so:

app.component.html excerpt:

        <div class="margin-20">
            <a (click)="addGroup(newName.value)" style="cursor: default">Add Group +</a>
          </div>

app.component.ts excerpt:

ngOnInit() {

        this.myForm = this._fb.group({    
        });
    }


 addGroup(newName:string) {

         let data = this._fb.group({
                     foo: ['what a load of foo'],
                     bar: ['see you at the bar']

                    })

        this.myForm.addControl(newName, data);
        document.getElementById('newName').value='';


    }

Working example in this plunk:

For an example where a corresponding input field is published for each formControl that is added in the new named group I created this plunk

Angular2: add and submit a new formGroup name and values with model driven form

1 Answers