a-cva-4.ts

// ... code of CounterComponent
writeValue(value: number) {
    // it's convenient to reuse existing "setValue" method, right?
    // however, this will lead to the incorrect behavior
    this.setValue(value, false);
    this._cdr.markForCheck();
}

protected setValue(value: number, emitEvent: boolean) {
    this.value = value;
    if (emitEvent && this.onChange) {
        this.onChange(value);
        this.onTouched();
    }
}