class Field extends React.Component {
  constructor(props) {
    super(props);
    this.state = {
      tasks: [
        'Необходимо купить молоко!',
        'Надо почистить зубы',
        'Просто отдохнуть'
      ]
    };
  };
  deleteBlock = (i) => {
    var arr = this.state.tasks;
    arr.splice (i, 1);
    this.setState ({tasks: arr});
  };
  updateText = (text, i) => {
    var arr = this.state.tasks;
    arr[i] = text;
    this.setState ({tasks: arr});
  };
  eachTask = (item, i) => {
    return (
      <Task key={i} index={i}>
        {item}
      </Task>
    );
  };
  render() {
    return (
      <div className="field">
        {this.state.tasks.map (this.eachTask)}
      </div>
    );
  }
}