title: Error: Cannot find control with path: 'specs -> 2' FormArray checkbox list
body: <p><a href="https://stackblitz.com/edit/angular-formarray-checkbox?file=app%2Fapp.component.html" rel="nofollow noreferrer">stackblitz</a></p>
  <p>I am using reactive forms and in my forms I have an array of string with which I bind my checkbox list.</p>
  <p>When I a trying to mark the returned array items to be selected, In console I am able to see the error</p>
  <p><a href="https://i.stack.imgur.com/TmUZg.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/TmUZg.png" alt="Error message in console " /></a></p>
  <p>.ts code as follow :</p>
  <pre><code>import { Component, OnInit } from '@angular/core';
  import { FormBuilder, FormGroup, FormArray, Validators } from '@angular/forms';
  
  @Component({
    selector: 'my-app',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
  })
  export class AppComponent {
    form: FormGroup;
  
    spec = ['site-1', 'site-2', 'site-4'];
  
    constructor(private fb: FormBuilder) {}
  
    ngOnInit() {
      this.form = this.fb.group({
        specs: this.fb.array(['site-1', 'site-2'].map(s =&gt; this.fb.control(true)))
      });
    }
  }
  </code></pre>
  <p>and html code as follow :</p>
  <pre><code>&lt;form [formGroup]=&quot;form&quot;&gt;
    &lt;div class=&quot;col-3&quot;&gt;
      &lt;div class=&quot;form-group&quot;&gt;
        &lt;b&gt;Select Spec Rows&lt;/b&gt;
      &lt;/div&gt;
  
      &lt;div class=&quot;form-group overflow&quot; formArrayName=&quot;specs&quot;&gt;
        &lt;div *ngFor=&quot;let site of spec; let i = index&quot;&gt;
          &lt;input
            type=&quot;checkbox&quot;
            [id]=&quot;i&quot;
            [formControlName]=&quot;i&quot;
            [value]=&quot;site&quot;
            (change)=&quot;specRowCheck($event,option.id, false)&quot;
          /&gt;
          &lt;div [innerHTML]=&quot;site&quot;&gt;&lt;/div&gt;
        &lt;/div&gt;
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/form&gt;
  </code></pre>
  <p><strong><code>ERROR Error: Cannot find control with path: 'specs -&gt; 2'</code></strong></p>
  <p>I checked other questions and its seems I am missing some form group in my html but I am not sure how to apply that</p>