@data-ui/xy-chart/esm/utils/findClosestDatums.js

A package of charts with standard x- and y- axes. https://williaster.github.io/data-ui

import { Children } from 'react';
import { localPoint } from '@vx/event';
import findClosestDatum from './findClosestDatum';
import { componentName, isSeries } from './chartUtils';
var DEFAULT_MAX_DISTANCE_PX = 1000;
export default function findClosestDatums(_ref) {
  var children = _ref.children,
      xScale = _ref.xScale,
      yScale = _ref.yScale,
      _ref$margin = _ref.margin,
      margin = _ref$margin === void 0 ? {} : _ref$margin,
      getX = _ref.getX,
      getY = _ref.getY,
      event = _ref.event,
      _ref$maxXDistancePx = _ref.maxXDistancePx,
      maxXDistancePx = _ref$maxXDistancePx === void 0 ? DEFAULT_MAX_DISTANCE_PX : _ref$maxXDistancePx;
  if (!event || !event.target || !event.target.ownerSVGElement) return null;
  var series = {};
  var gElement = event.target.ownerSVGElement;

  var _localPoint = localPoint(gElement, event),
      svgMouseX = _localPoint.x,
      svgMouseY = _localPoint.y;

  var mouseX = svgMouseX - (margin.left || 0);
  var mouseY = svgMouseY - (margin.top || 0);
  var closestDatum;
  var minDeltaX = Infinity;
  var minDeltaY = Infinity;
  var flatSeriesChildren = [];
  Children.forEach(children, function (Child) {
    var name = componentName(Child);

    if (name === 'AreaDifferenceSeries') {
      Children.forEach(Child.props.children, function (NestedChild) {
        flatSeriesChildren.push(NestedChild);
      });
    } else if (isSeries(name)) {
      flatSeriesChildren.push(Child);
    }
  }); // collect data from all series that have an x value near this point

  flatSeriesChildren.forEach(function (Child, childIndex) {
    if (!Child.props.disableMouseEvents) {
      var _Child$props = Child.props,
          data = _Child$props.data,
          seriesKey = _Child$props.seriesKey; // @TODO data should be sorted, come up with a way to enforce+cache instead of relying on user

      var datum = findClosestDatum({
        data: data,
        getX: getX,
        xScale: xScale,
        event: event,
        marginLeft: margin.left
      });
      var deltaX = Math.abs(xScale(getX(datum || {})) - mouseX);

      if (datum && deltaX <= maxXDistancePx) {
        var key = seriesKey || childIndex; // fall back to child index

        series[key] = datum;
        var deltaY = Math.abs(yScale(getY(datum)) - mouseY);
        closestDatum = deltaY < minDeltaY && deltaX <= minDeltaX ? datum : closestDatum;
        minDeltaX = closestDatum === datum ? deltaX : minDeltaX;
        minDeltaY = closestDatum === datum ? deltaY : minDeltaY;
      }
    }
  });
  return {
    series: series,
    closestDatum: closestDatum
  };
}