Angular 2 Accessing Nested FormArrays using FormBuilder

Question

First of all I just begin with Angular 2 and I'm trying to build a nested form and validate it.

Here's part of my ts file:

ngOnInit() {
  this.myForm = this.formBuilder.group({
    projects: this.formBuilder.array([
      this.initProjects()
    ])
  });
}

initProjects(): any {
  return this.formBuilder.group({
    name: ['', [Validators.required, Validators.minLength(3)]],
    some_array: this.formBuilder.array([
      this.formBuilder.group({
        name: ['', Validators.required],
        attr: ['', Validators.required],
        some_id: [1, Validators.required]
      })
    ])
  });
}

addProject(): void {
  const control = < FormArray > this.myForm.controls['projects'];
  control.push(this.initProjects());
}

View:

<form [formGroup]="myForm" novalidate (ngSubmit)="onSubmit(myForm)">
  <div formArrayName="projects">
    <div *ngFor="let project of myForm.controls.projects.controls; let i = index">
      <div [formGroupName]="i">
        <md-input placeholder="Name" formControlName="name"></md-input>
      </div>
      <div *ngFor="let some_obj of project.controls.some_array.controls; let x = index">
        <div [formGroupName]="x">
          <div>
            <md-input placeholder="Nome" formControlName="controls.some_array.controls.name"></md-input>
            <small *ngIf="!some_obj.controls.name.valid">
                    Nome é requerido
                  </small>
          </div>
          <md-input type="number" placeholder="Cost" formControlName="controls.some_array.controls.attr" required></md-input>
        </div>
      </div>
    </div>
  </div>
  <button type="submit" md-raised-button color="primary" [disabled]="!myForm.valid">Submit</button>
</form>
<pre>form value: <br>{{myForm.value | json}}</pre>

The output of form value:

form value: 
{
  "projects": [
    {
      "name": "",
      "some_array": [
        {
          "name": "",
          "attr": "",
          "some_id": 1
        }
      ]
    },
    {
      "name": "",
      "some_array": [
        {
          "name": "",
          "attr": "",
          "some_id": 1
        }
      ]
    }
  ]
}

Well, as you can see I have some arrays called projects, with 1 array inside each one.

So the problem is that I'm not able to validate each control of some_array array.

Actually I'm getting the following error:

ORIGINAL EXCEPTION: Cannot find control with path: 'projects -> 0 -> controls.some_array.controls.name PS: I already tried to put it in a div, as below:

But I also got an error:

Cannot find control with path: 'projects -> some_array' Thanks in advance. Any help would be appreciated.

Solution

Try the following HTML:

<form [formGroup]="myForm" novalidate (ngSubmit)="onSubmit(myForm)">
    <div formArrayName="projects">
        <div [formGroupName]="i" *ngFor="let project of myForm.controls.projects.controls; let i = index">
            <md-input placeholder="Name" formControlName="name"></md-input>
            <div formArrayName="some_array">
                <div [formGroupName]="x" *ngFor="let some_obj of project.controls.some_array.controls; let x = index">
                    <div>
                        <md-input placeholder="Nome" formControlName="name"></md-input>
                        <small *ngIf="!some_obj.controls.name.valid">Nome é requerido</small>
                    </div>
                    <md-input type="number" placeholder="Cost" formControlName="attr" required></md-input>
                </div>
            </div>
        </div>
    </div>
    <button type="submit" md-raised-button color="primary" [disabled]="!myForm.valid">Submit</button>
</form>
<pre>form value: <br>{{myForm.value | json}}</pre>