Angular 2 Reactive form + directive validation - forms

Question

I'm trying to wrap my head around the following problem:
I have a 'google-place-autocomplete' directive that adds the autocomplete functionality to an input field.
Now I also wanted it to be able to force a google place selection and only be 'valid' if the user has selected a place.
E.g:
#Directive({
selector: '[googlePlace][formControlName], [googlePlace][ngModel]',
providers: [{provide: NG_VALIDATORS, useExisting: GooglePlaceDirective, multi: true}]
})
export class GooglePlaceDirective implements Validator, OnChanges {
valid = false;
#Output() googlePlaceAddressChange: any = new EventEmitter();
#Input() googlePlaceAddress: any;
#Output() ngModelChange: any = new EventEmitter();
private autocomplete: any;
constructor(private googleMapService: GoogleMapsService,
private element: ElementRef,
private zone: NgZone) {
}
ngOnInit() {
let self = this;
this.googleMapService
.load()
.subscribe(
() => {
this.autocomplete = new google.maps.places.Autocomplete(this.element.nativeElement);
this.autocomplete.addListener('place_changed', function () {
self.placeChanged(this.getPlace());
});
}
);
}
private placeChanged(place) {
this.zone.run(() => {
this.googlePlaceAddress = {
address: this.element.nativeElement.value,
formattedAddress: place.formatted_address,
latitude: place.geometry.location.lat(),
longitude: place.geometry.location.lng()
};
this.valid = true;
this.googlePlaceAddressChange.emit(this.googlePlaceAddress);
this.ngModelChange.emit(this.element.nativeElement.value);
});
}
ngOnChanges(changes): void {
let googlePlaceDefined = typeof (changes.googlePlaceAddress) !== 'undefined';
let modelDefined = typeof (changes.ngModel) !== 'undefined';
if(modelDefined && !googlePlaceDefined) {
this.valid = false;
} else if(googlePlaceDefined && !modelDefined) {
this.valid = true;
}
}
validate(control: AbstractControl) {
return this.valid === false ? {'googlePlaceAddress': true} : null;
}
}
If I use this directive in an template driven form:
...
<input name="addr" type="text" [(ngModel)]="textValue" [(googlePlaceAddress)]="googleAddress" required>
<p *ngIf="addr.errors.googlePlaceAddress">Please select a proposed address</p>
...
it works fine.
Now I need to use this in an Reactive Form using FormGroup
let groups = [
new FormControl('', [Validators.required])
];
/** HTML **/
...
<input [id]="addr"
[formControlName]="address"
class="form-control"
type="text"
googlePlace
[placeholder]="question.label"
[(googlePlaceAddress)]="googleAddress">
...
However in this case the validation from the directive is never triggered.
I suppose angular2 expects it to be given through, when using Reactive Forms:
new FormControl('', [Validators.required, ???])
I must have taken a wrong path somewhere.

Answer 1

For future reference:
I solved my problem creating a component out of it together with a Value accessor:
#Component({
selector: 'app-google-place',
templateUrl: './google-place.component.html',
styleUrls: ['./google-place.component.scss'],
providers: [
{
provide: NG_VALUE_ACCESSOR,
useExisting: forwardRef(() => GooglePlaceComponent),
multi: true
}
]
})
export class GooglePlaceComponent implements OnInit, ControlValueAccessor {
#ViewChild('inputElement') inputElement: ElementRef;
#Input() public placeholder: string = "Address";
#Input() public textValue: string = "";
private autocomplete: any;
private _place = null;
constructor(
private googleMapService: GoogleMapsService,
private zone: NgZone
) {
}
ngOnInit() {
this.googleMapService
.load()
.subscribe(
() => {
this.autocomplete = new google.maps.places.Autocomplete(this.inputElement.nativeElement);
this.autocomplete.addListener('place_changed', () => this.placeChanged());
}
);
}
placeChanged() {
this.zone.run(() => {
let place = this.autocomplete.getPlace();
this._place = {
address: this.inputElement.nativeElement.value,
formattedAddress: place.formatted_address,
latitude: place.geometry.location.lat(),
longitude: place.geometry.location.lng()
};
this.propagateChange(this._place);
});
}
onNgModelChange($event) {
if(this._place !== null) {
if(this._place.address !== $event) {
this._place = null;
this.propagateChange(this._place);
}
}
}
onBlur() {
this.propagateTouched();
}
writeValue(obj: any): void {
if(obj !== undefined) {
this._place = obj;
}
}
propagateChange = (_: any) => {};
registerOnChange(fn) {
this.propagateChange = fn;
}
propagateTouched = () => {};
registerOnTouched(fn: any): void {
this.propagateTouched = fn;
}
}
Using this I can use it in a FormGroup with the Validators.required and it will only be valid if a user has selected a google place.
EDIT
The html:
<input type="text"
(blur)="onBlur()"
#inputElement
class="form-control"
[(ngModel)]="textValue"
(ngModelChange)="onNgModelChange($event)">
The service:
import {Injectable} from '#angular/core';
import {Subject} from 'rxjs/Subject';
import {Observable} from 'rxjs/Observable';
#Injectable()
export class GoogleMapsService {
private key = 'XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX';
private loaded = false;
private currentRequest = null;
constructor() {
}
load() {
if (this.loaded) {
return Observable.create((observer) => {
observer.next();
observer.complete();
});
}
if (this.currentRequest === null) {
//http://reactivex.io/rxjs/manual/overview.html#multicasted-observables
const source = Observable.create((observer) => {
this.loadMaps(observer);
});
const subject = new Subject();
this.currentRequest = source.multicast(subject);
this.currentRequest.connect();
}
return this.currentRequest;
}
private loadMaps(observer: any) {
const script: any = document.createElement('script');
script.src = 'https://maps.googleapis.com/maps/api/js?key=' + this.key + '&libraries=places';
if (script.readyState) { // IE, incl. IE9
script.onreadystatechange = () => {
if (script.readyState == 'loaded' || script.readyState == 'complete') {
script.onreadystatechange = null;
this.loaded = true;
observer.next();
observer.complete();
this.currentRequest = null;
}
};
} else {
script.onload = () => { // Other browsers
this.loaded = true;
observer.next();
observer.complete();
this.currentRequest = null;
};
}
script.onerror = () => {
observer.error('Unable to load');
this.currentRequest = null;
};
document.getElementsByTagName('head')[0].appendChild(script);
}
}
The 'usage':
With template ngModel
<app-google-place ([ngModel)]="place"></app-google-place>