How to use the dygraphs/src/dygraph.VERSION function in dygraphs

Dygraph.prototype.findClosestPoint = function(domX, domY) {
  if (Dygraph.VERSION !== '2.0.0') {
    console.error(
      `Dygraph version changed to ${Dygraph.VERSION} - re-copy findClosestPoint`
    )
  }
  let minXDist = Infinity
  let minYDist = Infinity
  let xdist, ydist, dx, dy, point, closestPoint, closestSeries, closestRow
  for (let setIdx = this.layout_.points.length - 1; setIdx >= 0; --setIdx) {
    const points = this.layout_.points[setIdx]
    for (let i = 0; i < points.length; ++i) {
      point = points[i]
      if (!isValidPoint(point, null)) {
        continue
      }

      dx = point.canvasx - domX
      dy = point.canvasy - domY

Dygraph.prototype.findClosestPoint = function(domX, domY) {
  if (Dygraph.VERSION !== '2.0.0') {
    console.error(
      `Dygraph version changed to ${Dygraph.VERSION} - re-copy findClosestPoint`
    )
  }
  let minXDist = Infinity
  let minYDist = Infinity
  let xdist, ydist, dx, dy, point, closestPoint, closestSeries, closestRow
  for (let setIdx = this.layout_.points.length - 1; setIdx >= 0; --setIdx) {
    const points = this.layout_.points[setIdx]
    for (let i = 0; i < points.length; ++i) {
      point = points[i]
      if (!isValidPoint(point, null)) {
        continue
      }

      dx = point.canvasx - domX