Cannot pass value to parent component in React.Js - reactjs

Question

I'm strugelling with that one.
I'm trying to build a calendar using react-calendar package. In one place of my app I need to have an access to the calendar month's value. I'm calling the components property onActiveDateChange which I found in docs of the component (react-calendar). It is indeed a callback so I'm trying to use it as my chance to extract month value and send it up to the parent component. But that does not work, not only the value is not changed as expected, but the calendar stops working. Do you know what is causing that? I've tried also with setting a state in the callback but the same results, value is not correct.
Here's my chunk of code:
import React, { Component } from 'react';
import Calendar from 'react-calendar';
import ChooseHour from './ChooseHour';
import { connect } from 'react-redux';
import * as actions from '../actions';
class Calendario extends Component {
state = { showHours: false,}
onChange = date => this.setState({
date }, () => {
const { chosenRoom } = this.props;
const year = date.getFullYear();
const month = date.getMonth() + 1;
const day = date.getDate();
const fullDate = `${year}/${month}/${day}`;
const roomAndDayObj = {fullDate, chosenRoom};
this.props.sendRoomAndDay(roomAndDayObj);
}
)
onClickDay(e) {
this.setState({ showHours: true });
}
passActiveDate(activeDate) {
const monthAfterPress = activeDate.getMonth() + 1;
console.log(monthAfterPress);
// this is weird in my opinion, I can log it and it works as expected,
// when I'm firing the next line the values are incorrect
// this.props.activeMonthToPass(monthAfterPress); //this line makes a problem
}
render() {
const { booked } = this.props;
return (
<div>
<div className="calendarsCont">
<Calendar
onChange={this.onChange}
onClickDay={(e) => this.onClickDay(e)}
onActiveDateChange={({ activeStartDate }) => this.passActiveDate(activeStartDate)}
value={this.state.date}
locale="pl-PL"
tileDisabled={({date, view }) =>
date.getDate()===15 && date.getMonth()===6 && date.getFullYear()===2018}
/>
</div>
<div>
{this.state.showHours ?
<ChooseHour chosenDay={this.state.date} chosenRoom={this.props.chosenRoom}/> :
null}
</div>
</div>
)
}
}
export default connect (null, actions)(Calendario);