interface IProps {
}

interface IState {
  playOrPause?: string;
}

class Player extends React.Component {
  // ------------------------------------------^
  constructor(props: IProps) {
    super(props);

    this.state = {
      playOrPause: 'Play'
    };
  }

  render() {
    return(
      

         this.playPause = playPause}
          title={this.state.playOrPause} // in this line I get an error
        >
          Play
        
      
    );
  }
}