sample-new-comment.jsx

import React from 'react';
import { connect } from 'react-redux';

class NewComment extends React.Component {

  input = null
  
  writeComment = evt => {
    evt.preventDefault();
    const comment = this.input.value;
    
    comment && this.props.dispatch({ type: 'WRITE_COMMENT', comment });
  }
  
  render() {
    const { id, content } = this.props.comment;
    
    return (
      <div>
        <input type="text" ref={e => this.input = e} placeholder="Write a comment" />
        <button type="button" onClick={this.writeComment}>Submit Comment</button>
      </div>
    )
  }
  
}

export default connect()(NewComment);