title: Type 'FormArray' is not assignable to type 'any[]'. Property 'includes' is missing in type 'FormArray'. in angular6 typescript
body: <p>How to solve the below-mentioned Error:</p>
  
  <blockquote>
    <p>Type 'FormArray' is not assignable to type 'any[]'.   Property
    'includes' is missing in type 'FormArray'.
    in line " this.items = this.AddUserstep2Form.get('items') as FormArray;"</p>
  </blockquote>
  
  <p>I have the below-mentioned ts file. Please help me.</p>
  
  <pre><code>import { FormBuilder, FormGroup, Validators ,FormArray} from '@angular/forms';
  
   AddUserstep2Form: FormGroup;   items: any[] = [];
  
   ngOnInit() {
      this.AddUserstep2Form = this.fb.group({
  
        stateCode: ['',Validators.required],
        cityId:['',Validators.required],
        items: this.fb.array([ this.createItem() ])
  
      })
  
  createItem(): FormGroup {
      return this.fb.group({
        stateCode: '',
        cityId: ''
      });
    }
    addItem(): void {
      this.items = this.AddUserstep2Form.get('items') as FormArray;
      this.items.push(this.createItem());
    }
  </code></pre>