How to update controls of FormArray : <p>My form group code is as</p>

<pre><code>this.myForm = this._fb.group({            
            branch_name: ['', [Validators.required]],
            branch_timing: this._fb.array([
                this.initBranchTiming(),
            ])                                
        });

initBranchTiming() {       
        return this._fb.group({
            day: ['', []],
            open_from: ['00:00:00', []],
            open_till: ['00:00:00', []]           
        });
  }
</code></pre>

<p>branch_name is updated by this code   </p>

<pre><code>(&lt;FormControl&gt;this.myForm.controls['branch_name']).updateValue(this.branch_detail.branch_name);
</code></pre>

<p>Now i have to update the 'day' field of form array. what to do to update the 'day' field of form array branch_timing ?</p>
