a-cva-3.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);
    this._cdr.markForCheck();
}

protected setValue(value: number) {
    const parsed = parseInt(value as any);
    this.value = isNaN(parsed) ? 0 : parsed;
    if (this.onChange) {
        this.onChange(value);
        this.onTouched();
    }
}