voronoi.js

import React from 'react';

import Sankey from 'sankey';

const BLURRED_NODE_OPACITY = 0.8;
const FOCUSED_NODE_OPACITY = 1;

const nodes = [{name: 'a'}, {name: 'b'}, {name: 'c'}];
const links = [
  {source: 0, target: 1, value: 10},
  {source: 0, target: 2, value: 20},
  {source: 1, target: 2, value: 20}
];

export default class VoronoiSankeyExample extends React.Component {
  state = {
    activeNode: null
  };

  render() {
    const {activeNode} = this.state;

    // Note: d3.sankey currently mutates the `nodes` and `links` arrays, which doesn't play nice
    // with React's single-direction data flow. We create a copy of each before we pass to the sankey
    // component, just to be sure.
    return (
      <div>
        <div>{`${activeNode ? activeNode.name : 'None'} selected`}</div>
        <Sankey
          nodes={nodes.map(d => {
            const isActiveNode = activeNode && d.name === activeNode.name;
            return {
              ...d,
              opacity: isActiveNode
                ? FOCUSED_NODE_OPACITY
                : BLURRED_NODE_OPACITY,
              name: isActiveNode ? `!${d.name}!` : d.name
            };
          })}
          links={links.map(d => ({...d}))}
          width={200}
          height={200}
          hasVoronoi
          onValueMouseOver={node => this.setState({activeNode: node})}
          onValueMouseOut={() => this.setState({activeNode: null})}
        />
      </div>
    );
  }
}