react-vega -获取点击事件的数据(为点击事件添加事件侦听器)

import { createClassFromSpec } from 'react-vega';
import { Handler } from 'vega-tooltip';

const spec = {
  "$schema": "https://vega.github.io/schema/vega-lite/v5.json",
  "data": {
    "values": [
      {"category": "A", "value": 28},
      {"category": "B", "value": 55},
      {"category": "C", "value": 43},
      {"category": "D", "value": 91},
      {"category": "E", "value": 81},
      {"category": "F", "value": 53},
      {"category": "G", "value": 19},
      {"category": "H", "value": 87}
    ]
  },
  "mark": "bar",
  "encoding": {
    "x": {"field": "category", "type": "ordinal"},
    "y": {"field": "value", "type": "quantitative"}
  },
  "config": {
    "view": {"continuousWidth": 400, "continuousHeight": 300}
  },
  "selection": {
    "click": {"type": "single", "encodings": ["x"], "on": "click"}
  }
};

const MyChart = createClassFromSpec(spec, { handler: new Handler().call });

class App extends React.Component {
  handleClick(event, item) {
    console.log('Clicked:', item.datum);
  }

  render() {
    return (
      <div>
        <MyChart
          onSignalClick={this.handleClick}
        />
      </div>
    );
  }
}