我有一个从 API 获取数据的动态复选框，以下是 html 文件

<form [formGroup]="form" (ngSubmit)="submit()">
  <label formArrayName="summons" *ngFor="let order of form.controls.summons.controls; let i = index">
    <input type="checkbox" [formControlName]="i">
    {{summons[i].name}}
  </label>

  <div *ngIf="!form.valid">At least one order must be selected</div>
  <br>
  <button [disabled]="!form.valid">submit</button>
</form>

以下是 typescript 文件：

interface Item {
  offenceType4: string;
  permSpeed: string;
  actSpeed: string;
  itemAttributes: ItemAttributes;
  offenceLoc: string;
  itemNo: string;
  summonDate: string;
  distCode: string;
  summonType: string;
  hbtlOffndr: string;
  itemAmount: number;
  itemAttributesCount: number;
  summonAmt: string;
  offenceType1: string;
  offenceCode1: string;
  offenceType2: string;
  offenceCode2: string;
  offenceType3: string;
  category: string;
  offenceCode3: string;
  offenceCode4: string;
  respCode: string;
}

interface ItemAttributes {
  attribute5: string;
  attribute4: string;
  attribute7: string;
  attribute6: string;
  attribute1: string;
  attribute3: string;
  attribute2: string;

}
  interface RootObject {
  items: Item[];
  status: Status;
  additionalProperties: AdditionalProperties;
  metadata: Metadata;
}

export class InquiryResponseMultiselectComponent implements OnInit {
  form: FormGroup;
  summons = [];
  data: any[];

  constructor(
    private formBuilder: FormBuilder,
    private inquiryService: InquiryService
  ) {
    this.form = this.formBuilder.group({
      summons: new FormArray([], minSelectedCheckboxes(1)),
    });

     this.getSummon().subscribe(summons => {
      this.summons = summons;
      this.addCheckboxes();
    });
  }

  ngOnInit() {
    this.getSummon();
  }

  getSummon() {
    return this.inquiryService.getData().pipe(map((item: RootObject) => 
  item.items)) ;
  }

  addCheckboxes() {
    this.summons.map(i => {
    const control = new FormControl();
    const formArray = this.form.controls.summons as FormArray;
    formArray.push(control);
    });
  }

我从 API 获得对动态复选框的响应，然后，我需要将新控件推送到 summons FormArray ，但我收到错误

core.js:9110 ERROR TypeError: Cannot read property 'map' of undefined

如果我不进行类似这样的映射：

  addCheckboxes() {
      const control = new FormControl();
      const formArray = this.form.controls.summons as FormArray;
      formArray.push(control);
  }

我将获得默认的 formControl 长度等于 1，这是我不想要的，需要建议和指导我如何解决这个问题，