Error TS2339: Property 'ITEMS' does not exist on type 'DataModel[]'

问题

I get this error message: TS2339: Property 'ITEMS' does not exist on type 'DataModel[]'

I'm working in IONIC/ANGULAR and doing a reactive Form with a model and getting data from HTTP.

There is the model (model.ts):

export class DataModel {
    public ITEMS: any[];

    constructor(public NAME: string, public QUANTITY: Array<string>) {
        this.ITEMS = [{NAME, QUANTITY}];
    }
}

There is the code part where the error come from of the form.page.ts

  setItems() {
    const control = this.itemsForm.controls.items as FormArray;
    this.dbData.ITEMS.forEach(element => {
      control.push(
        this.formBuilder.group({
          name: element.NAME,
          quantity: this.setItem(element)
        })
      );
    });
  }

There is the full code form.page.ts

export class Form2Page implements OnInit, OnDestroy {
  obsSubscription: Subscription;
  itemsForm: FormGroup;

  public dbData: DataModel[];


  constructor(
    private formBuilder: FormBuilder,
    private storageService: FormStorageService
  ) {}

  ngOnInit() {
    // Get data from DB
    this.storageService.getDBData();
    this.obsSubscription = this.storageService.dbSubject.subscribe(
      (value: any[]) => {
        this.dbData = value;

    // Creating the FORM
        this.initForm();
        this.setItems();
      },
      error => {
        console.log('erreur');
        console.log(error);
      }
    );
  }

  initForm() {
    this.itemsForm = new FormGroup({
      items: new FormArray([])
    });
  }

  setItems() {
    const control = this.itemsForm.controls.items as FormArray;
    this.dbData.ITEMS.forEach(element => {
      control.push(
        this.formBuilder.group({
          name: element.NAME,
          quantity: this.setItem(element)
        })
      );
    });
  }

  setItem(value) {
    const array = new FormArray([]);
    value.QUANTITY.forEach(element => {
      array.push(this.formBuilder.control(element));
    });
    return array;
  }

  findFieldArray(field: any): FormArray {
    return this.itemsForm.get(field) as FormArray;
  }

  addNewItems() {
    const control = this.itemsForm.controls.items as FormArray;
    control.push(
      this.formBuilder.group({
        name: '',
        quantity: this.formBuilder.array([this.formBuilder.control('')])
      })
    );
  }

  addNewItem(item: FormGroup) {
    (item.get('quantity') as FormArray).push(this.formBuilder.control(''));
  }

  removeItem(item: FormGroup, qtyIndex: number, itemIndex: number) {
    (item.get('quantity') as FormArray).removeAt(qtyIndex);
  }

  removeItems(itemIndex: number) {
    const form = this.itemsForm.get('items') as FormArray;
    form.removeAt(itemIndex);
  }

  checkArray(itemIndex: number) {
        // Get the quantity array lenght to display the remove ITEMS button
        return ((this.itemsForm.get('items') as FormArray)
        .at(itemIndex)
        .get('quantity') as FormArray).length;
  }

  onFormSubmit() {
    console.log('Submit : ', this.itemsForm.value);
  }

  ngOnDestroy() {
    this.obsSubscription.unsubscribe();
  }
}

Thanks for your help

回答1:

dbData is a DataModel[] , you access it as this.dbData.ITEMS which for sure doesn't exists. so either you have to

dbData : DataModel;

this.dbData.ITEMS...

or

dbData : DataModel[];

this.dbData.forEach(dbItem => {

   dbItem.ITEMS...
})

also I noticed DataModel has an array inside, I guess you meant to have one DataModel not an array

回答2:

since you defined public dbData: DataModel[] as an array you should treat it as one.

My guess is you meant to define it as public dbData: DataModel, then it will work when you call this.dbData.ITEMS.forEach(element => {

Here is the full change:

export class Form2Page implements OnInit, OnDestroy {
  obsSubscription: Subscription;
  itemsForm: FormGroup;

  public dbData: DataModel;  // #1 change


  constructor(
    private formBuilder: FormBuilder,
    private storageService: FormStorageService
  ) {}

  ngOnInit() {
    // Get data from DB
    this.storageService.getDBData();
    this.obsSubscription = this.storageService.dbSubject.subscribe(
      (value: any[]) => {
        this.dbData = { ITEMS: value };  // #2 change

    // Creating the FORM
        this.initForm();
        this.setItems();
      },
      error => {
        console.log('erreur');
        console.log(error);
      }
    );
  }

  initForm() {
    this.itemsForm = new FormGroup({
      items: new FormArray([])
    });
  }

  setItems() {
    const control = this.itemsForm.controls.items as FormArray;
    this.dbData.ITEMS.forEach(element => {
      control.push(
        this.formBuilder.group({
          name: element.NAME,
          quantity: this.setItem(element)
        })
      );
    });
  }

  setItem(value) {
    const array = new FormArray([]);
    value.QUANTITY.forEach(element => {
      array.push(this.formBuilder.control(element));
    });
    return array;
  }

  findFieldArray(field: any): FormArray {
    return this.itemsForm.get(field) as FormArray;
  }

  addNewItems() {
    const control = this.itemsForm.controls.items as FormArray;
    control.push(
      this.formBuilder.group({
        name: '',
        quantity: this.formBuilder.array([this.formBuilder.control('')])
      })
    );
  }

  addNewItem(item: FormGroup) {
    (item.get('quantity') as FormArray).push(this.formBuilder.control(''));
  }

  removeItem(item: FormGroup, qtyIndex: number, itemIndex: number) {
    (item.get('quantity') as FormArray).removeAt(qtyIndex);
  }

  removeItems(itemIndex: number) {
    const form = this.itemsForm.get('items') as FormArray;
    form.removeAt(itemIndex);
  }

  checkArray(itemIndex: number) {
        // Get the quantity array lenght to display the remove ITEMS button
        return ((this.itemsForm.get('items') as FormArray)
        .at(itemIndex)
        .get('quantity') as FormArray).length;
  }

  onFormSubmit() {
    console.log('Submit : ', this.itemsForm.value);
  }

  ngOnDestroy() {
    this.obsSubscription.unsubscribe();
  }
}

Finally you should change:

public dbData: DataModel[]; -> public dbData: DataModel;

this.dbData = value -> this.dbData = { ITEMS: value };

回答3:

Ther is the source code with the error you can see in the code in red.

Source Code with the error

来源：https://stackoverflow.com/questions/56888106/error-ts2339-property-items-does-not-exist-on-type-datamodel