OpenLayers - GeoJSON with mouseover infos

OpenLayers map using Proj4js reprojecting GeoJSON data with mouseover function.

HTML:

<div id='map'></div>
<i id="info"></i>

Javascript:

proj4.defs('EPSG:8857', '+proj=eqearth +lon_0=0 +x_0=0 +y_0=0 +R=6371008.7714 +units=m +no_defs +type=crs');
ol.proj.proj4.register(proj4);

const extent = [-17243959.06, -17243959.06, 17243959.06, 17243959.06];

const vectorLayer = new ol.layer.Vector({
  source: new ol.source.Vector({
    url: 'https://openlayers.org/data/vector/ecoregions.json',
    format: new ol.format.GeoJSON(),
  }),
  style: {
    'fill-color': ['string', ['get', 'COLOR'], '#eee'],
  },
});

const map = new ol.Map({
  layers: [vectorLayer],
  target: 'map',
  view: new ol.View({
    center: [0, 0],
    projection: 'EPSG:8857',
    extent: extent,
    zoom: 0
  }),
});

const featureOverlay = new ol.layer.Vector({
  source: new ol.source.Vector(),
  map: map,
  style: {
    'stroke-color': 'rgba(255, 255, 255, 0.7)',
    'stroke-width': 2,
  },
});

let highlight;
const displayFeatureInfo = function (pixel) {
  const feature = map.forEachFeatureAtPixel(pixel, function (feature) {
    return feature;
  });

  const info = document.getElementById('info');
  if (feature) {
    info.innerHTML = feature.get('ECO_NAME') || ' ';
  } else {
    info.innerHTML = ' ';
  }

  if (feature !== highlight) {
    if (highlight) {
      featureOverlay.getSource().removeFeature(highlight);
    }
    if (feature) {
      featureOverlay.getSource().addFeature(feature);
    }
    highlight = feature;
  }
};

map.on('pointermove', function (evt) {
  if (evt.dragging) {
    return;
  }
  const pixel = map.getEventPixel(evt.originalEvent);
  displayFeatureInfo(pixel);
});

map.on('click', function (evt) {
  displayFeatureInfo(evt.pixel);
});

Header:

<script src="https://cdn.jsdelivr.net/npm/ol@9.1.0/dist/ol.js"></script>
<link href="https://cdn.jsdelivr.net/npm/ol@9.1.0/ol.min.css" rel="stylesheet">
<script src="https://cdn.jsdelivr.net/npm/proj4@2.11.0/dist/proj4.min.js"></script>