@visx/xychart/esm/utils/findNearestDatumXY.js

Composable cartesian coordinate chart built with visx primitives

import { voronoi } from '@visx/voronoi';
/* finds the datum nearest to svgMouseX/Y using a voronoi */
export default function findNearestDatumXY(_ref) {
  var width = _ref.width,
    height = _ref.height,
    xScale = _ref.xScale,
    yScale = _ref.yScale,
    xAccessor = _ref.xAccessor,
    yAccessor = _ref.yAccessor,
    point = _ref.point,
    data = _ref.data;
  if (!point) return null;
  var scaledX = function scaledX(d) {
    return Number(xScale(xAccessor(d)));
  };
  var scaledY = function scaledY(d) {
    return Number(yScale(yAccessor(d)));
  };

  // Create a voronoi for each datum's x,y coordinate
  var voronoiInstance = voronoi({
    x: scaledX,
    y: scaledY,
    width: width,
    height: height
  });
  var nearestDatum = voronoiInstance(data).find(point.x, point.y);
  if (!nearestDatum) return null;
  var datum = nearestDatum.data,
    index = nearestDatum.index;
  var distanceX = Math.abs(scaledX(datum) - point.x);
  var distanceY = Math.abs(scaledY(datum) - point.y);
  return {
    datum: datum,
    index: index,
    distanceX: distanceX,
    distanceY: distanceY
  };
}