Recursive form (tree view) using Reactive forms in angular 6

I have understand concept of recursive elements(tree view) from below.

Link 1

In my case, I want to use it with forms; let's say simple text input recursively. JSON structure of form is as below.

JOSN Structure

I have prepared below code.I am getting Maximum call stack size exceeded error by executing below code.

Below is my component.html file.

<form [formGroup]="testForm" (ngSubmit)="onSubmit()">
    <div formArrayName="element">
        <ng-template #recursiveList let-list>       
              <div *ngFor="let item of testForm.get('element').controls;let i=index;">     
                  <div [formGroupName]="i">
                    <input type="text" formControlName="type">
                  </div> 
                  <!--  -->
                  <div *ngIf="item.get('element')?.controls?.length > 0">          
                    <ng-container *ngTemplateOutlet="recursiveList; context:{ $implicit: item.get('element').controls }"></ng-container>
                  </div>
              </div>          
        </ng-template>
        <ng-container *ngTemplateOutlet="recursiveList; context:{ $implicit: testForm.get('element').controls }"></ng-container>
    </div>     

And here is component.ts file.

import { Component, OnInit } from '@angular/core';
import {FormControl, FormGroup, Validators, FormBuilder, FormArray} from '@angular/forms';

@Component({
    selector: 'app-test',
    templateUrl: './test.component.html',
    styleUrls: [
      './test.component.scss'
    ]
  })
export class TestComponent implements OnInit{
    testForm:FormGroup;
    element:any;

constructor(private formBuilder: FormBuilder) { }
ngOnInit() {

this.testForm=this.formBuilder.group({
  element:this.formBuilder.array([
    this.formBuilder.group({
      type:'',
      element:this.formBuilder.array([
        this.formBuilder.group({
          type:'',
          element:this.formBuilder.array([                
          ])
        })
      ])        
    })
  ])
})
}

onSubmit() {       
    console.log(this.testForm.value);
}
}

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