Angular 2: populate FormBuilder with data from http

Question

I get my data from http with rjsx in the component (let's call it customer).

Then I use the internal component in the client:

<customer>
  <customer-form [customer]="customer"></customer-form>
</customer>



<!-- [customer]="customer" // here is data from http -->

and in the client form I have:

@Input() customer:ICustomer;

complexForm : FormGroup;



constructor(fb: FormBuilder) {

  this.complexForm = fb.group({
    'name': [this.customer['name'], Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(255)])]
  });
}

but I get:

Cannot read property 'name' of undefined
TypeError: Cannot read property 'name' of undefined

if I understood correctly: this is because the constructor is called, but the data has not yet been received from http, so it is customerempty. But how to fix it?

upd: my http data get:

   getCustomer(id) {
    this.customerService.getCustomer(id)
      .subscribe(
        customer => this.customer = customer,
        error =>  this.errorMessage = <any>error);
  }
  ----


@Injectable()
export class CustomerService {

  private customersUrl = 'api/customer';

  constructor (private http: Http) {}

  getCustomers (): Observable<ICustomer[]> {
    return this.http.get(this.customersUrl)
      .map(this.extractData)
      .catch(this.handleError);
  }

  getCustomer (id): Observable<ICustomer> {
    return this.http.get(this.customersUrl + '/' + id)
      .map(this.extractData)
      .catch(this.handleError);
  }



  private extractData(res: Response) {
    let body = res.json();
    return body || { };
  }


  private handleError (error: Response | any) {
    // In a real world app, we might use a remote logging infrastructure
    let errMsg: string;
    if (error instanceof Response) {
      const body = error.json() || '';
      const err = body.error || JSON.stringify(body);
      errMsg = `${error.status} - ${error.statusText || ''} ${err}`;
    } else {
      errMsg = error.message ? error.message : error.toString();
    }
    console.error(errMsg);
    return Observable.throw(errMsg);
  }

}

Answer 1

as @Bhushan Gadekar said, you are accessing the client when it was not initialized.

There are several ways to handle this correctly:

Using the setter:

@Input("customer") 
set _customer(c:ICustomer){
  this.customer=c;
  this.complexForm.get("name").setValue(c.name,{onlySelf:true});
}
customer:ICustomer;
complexForm : FormGroup;

constructor(fb: FormBuilder) {

  this.complexForm = fb.group({
    'name': [null, Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(255)])]
  });
}

Using Observable

Here the customer should be Observable ICustomer

@Input() customer:Observable<ICustomer>;

complexForm : FormGroup;

constructor(fb: FormBuilder) {
  this.complexForm = fb.group({
    'name': [this.customer['name'], Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(255)])]
  });
}

ngOnInit(){
  this.customer.map(c=>this.complexForm.get("name").setValue(c.name,{onlySelf:true}))
  .subscribe();
}

:

@Input("customer") 
set _customer(c:ICustomer){
  this.customer.next(c);
}
customer=New Subject<ICustomer>();
complexForm : FormGroup;

constructor(fb: FormBuilder) {
  this.complexForm = fb.group({
    'name': [null, Validators.compose([Validators.required, Validators.minLength(3), Validators.maxLength(255)])]
  });
}

ngOnInit(){
  this.customer.map(c=>this.complexForm.get("name").setValue(c.name,{onlySelf:true}))
  .subscribe();
}

:

, , :

Object.keys(customer).forEach(k=>{
  let control = this.complexForm.get(k);
  if(control)
    control.setValue(customer[k],{onlySelf:true});
});

, , , . , - .

:

Yous , , ( , ) ngOnInit.

Answer 2

, customer, .

, HTTP- , . , , undefined.

:

<customer *ngIf="customer">
  <customer-form [customer]="customer"></customer-form>
</customer>

name . - className.propertyName

.

Answer 3

Instead of ngOnInit try ngAfterViewInit

Answer 4

do not use subscribein component.ts and add async channel in component.html, for example: <customer-form [customer]="customer | async"></customer-form>