how to JSON to Parse in react?

I have tree list components when I click on any item of the tree list it shows the result of JSON data. I don’t wanna JSON format but parse format.

i have tried let json = JSON.parse(this.props.node, null, 4); but it showing Unexpected token u in JSON at position 0

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class NodeViewer extends React.Component {
  constructor(props) {
    super(props);
  }
  render() {
    const style = styles.viewer;
    let json = JSON.stringify(this.props.node, null, 4);
    if (!json) {
      json = HELP_MSG;
    }
    return <div style={style.base}>{json}</div>;
  }
}

NodeViewer.propTypes = {
  node: PropTypes.object
};