message: feat(timepicker): allow null value and change validation state on manual update
diff: @@ -27,6 +27,7 @@ import {
  parseTime,
  isInputValid
  } from './timepicker.utils';
  +import { fakeAsync } from '@angular/core/testing';
  export const TIMEPICKER_CONTROL_VALUE_ACCESSOR: any = {
  provide: NG_VALUE_ACCESSOR,
  @@ -205,6 +206,7 @@ export class TimepickerComponent
  _updateTime() {
  const _seconds = this.showSeconds ? this.seconds : void 0;
  if (!isInputValid(this.hours, this.minutes, _seconds, this.isPM())) {
  + this.isValid.emit(false);
  this.onChange(null);
  return;
  @@ -239,6 +241,8 @@ export class TimepickerComponent
  writeValue(obj: any): void {
  if (isValidDate(obj)) {
  this._store.dispatch(this._timepickerActions.writeValue(parseTime(obj)));
  + } else if (obj == null) {
  + this._store.dispatch(this._timepickerActions.writeValue(null));
  }
  }
  