OpenLayers - Find point on polygon near mouse click

Modify Event

this.modifyInteraction = new Modify({
  // source: this.vectorSource, // all features in vector source
  features: this.selectInteraction.getFeatures(), // only selected features

  condition: (event) => {
    // clear out all selectedVertex properties on all features
    this.vectorLayer.getSource().forEachFeature((feature) => {
      feature.set("selectedVertex", undefined);
    });

    console.log("Modify Condition Fired:", event);
    const nearbyFeatures = this.map.getFeaturesAtPixel(event.pixel, { hitTolerance: 10 });
    console.log("Nearby features", nearbyFeatures);

    if (nearbyFeatures.length) {
      const eventPixel = event.pixel;
      const closestFeature = nearbyFeatures[0];
      const closestFeatureGeometry = closestFeature.getGeometry();
      const geometryType = closestFeatureGeometry.constructor.name;
      if (geometryType !== "Polygon") return true;

      const coordinatesOnClosestFeature = closestFeatureGeometry.getCoordinates()[0];
      const nearbyVertex = this.findVertexCloseEnoughToEvent(eventPixel, coordinatesOnClosestFeature);
      if (nearbyVertex) {
        console.log("Closest Feature:", closestFeature, "Closest vertex coordinates:", nearbyVertex);
        closestFeature.set("selectedVertex", nearbyVertex);
      } else {
        console.log("Closest Feature:", closestFeature, "Closest vertex coordinates:", "All are far away");
      }
    } else {
      console.log("all features are far away");
    }
    return true;
  },
});

findVertexCloseEnoughToEvent(eventPixel, coordinatesOnClosestFeature) {
  let minDistance;
  let closestCoordinate;

  coordinatesOnClosestFeature.forEach((coordinate) => {
    const coordinatePixels = this.map.getPixelFromCoordinate(coordinate);
    const dx = eventPixel[0] - coordinatePixels[0];
    const dy = eventPixel[1] - coordinatePixels[1];
    const distance = Math.sqrt(dx * dx + dy * dy);

    if (minDistance === undefined || distance < minDistance) {
      minDistance = distance;
      closestCoordinate = coordinate;
    }
  });

  if (minDistance < 20) {
    return closestCoordinate;
  } else {
    return undefined;
  }
}