Working

 function listTowns (selector) {

        let Form = React.createClass({
            render: function () {
                return (
                        <form onSubmit={this.props.onsubmit}>
                            <input type="text"/>
                            <input type="submit" value="Submit"/>
                        </form>
                )
            }
        });

        let List = React.createClass({
            render: function () {
                let cities = this.props.cities.filter(city => city !== '');
                cities = cities.map( (city, index) => <li key={index}>{city}</li>);
                return <ul>{cities}</ul>;
            }
        });

        let App = React.createClass({

            getInitialState: function () {
                return { cities: []}
            },
            onSubmitHandle: function (evt) {
                evt.preventDefault();
                let cities = evt.target.children[0].value.split(', ');
                this.setState({ cities: cities});
            },
            render: function () {
                return (
                    <div>
                        <Form onsubmit={this.onSubmitHandle} />
                        <List cities={this.state.cities} />
                    </div>
                )
            }

        });



        ReactDOM.render(
                <App />,
            document.getElementById(selector)
        );
    }