This example uses OpenLayers v10.9.0. The latest is v.
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#### Box Selection

DragBox 1 feature 12 selection 2 box 5

#####

Selected regions: None

Using a DragBox interaction to select features.

This example shows how to use a `DragBox` interaction to select features. Features are selected using a select interaction (`ol/interaction/Select`), to recieve highlighting and apply filters (features with color #CC6767 are not selectable)

Use `Ctrl+Drag` (`Command+Drag` on Mac) to draw boxes.

##### main.js

    import Map from 'ol/Map.js';
    import View from 'ol/View.js';
    import {platformModifierKeyOnly} from 'ol/events/condition.js';
    import {getWidth} from 'ol/extent.js';
    import GeoJSON from 'ol/format/GeoJSON.js';
    import DragBox from 'ol/interaction/DragBox.js';
    import Select from 'ol/interaction/Select.js';
    import VectorLayer from 'ol/layer/Vector.js';
    import VectorSource from 'ol/source/Vector.js';
    import Fill from 'ol/style/Fill.js';
    import Stroke from 'ol/style/Stroke.js';
    import Style from 'ol/style/Style.js';

    const vectorSource = new VectorSource({
      url: 'https://openlayers.org/data/vector/ecoregions.json',
      format: new GeoJSON(),
    });

    const style = new Style({
      fill: new Fill({
        color: '#eeeeee',
      }),
    });

    const map = new Map({
      layers: [
        new VectorLayer({
          source: vectorSource,
          background: '#1a2b39',
          style: function (feature) {
            const color = feature.get('COLOR_BIO') || '#eeeeee';
            style.getFill().setColor(color);
            return style;
          },
        }),
      ],
      target: 'map',
      view: new View({
        center: [0, 0],
        zoom: 2,
        constrainRotation: 16,
      }),
    });

    const selectedStyle = new Style({
      fill: new Fill({
        color: 'rgba(255, 255, 255, 0.6)',
      }),
      stroke: new Stroke({
        color: 'rgba(255, 255, 255, 0.7)',
        width: 2,
      }),
    });

    // a normal select interaction to handle click
    const select = new Select({
      filter: function (feature) {
        return !(feature.get('COLOR_BIO') === '#CC6767');
      },
      style: function (feature) {
        const color = feature.get('COLOR_BIO') || '#eeeeee';
        selectedStyle.getFill().setColor(color);
        return selectedStyle;
      },
    });
    map.addInteraction(select);

    // a DragBox interaction used to select features by drawing boxes
    const dragBox = new DragBox({
      condition: platformModifierKeyOnly,
    });

    map.addInteraction(dragBox);

    dragBox.on('boxend', function () {
      const boxExtent = dragBox.getGeometry().getExtent();

      // if the extent crosses the antimeridian process each world separately
      const worldExtent = map.getView().getProjection().getExtent();
      const worldWidth = getWidth(worldExtent);
      const startWorld = Math.floor((boxExtent[0] - worldExtent[0]) / worldWidth);
      const endWorld = Math.floor((boxExtent[2] - worldExtent[0]) / worldWidth);

      for (let world = startWorld; world <= endWorld; ++world) {
        const left = Math.max(boxExtent[0] - world * worldWidth, worldExtent[0]);
        const right = Math.min(boxExtent[2] - world * worldWidth, worldExtent[2]);
        const extent = [left, boxExtent[1], right, boxExtent[3]];

        const boxFeatures = vectorSource
          .getFeaturesInExtent(extent)
          .filter((feature) => feature.getGeometry().intersectsExtent(extent));

        // features that intersect the box geometry are added to the
        // collection of selected features

        // if the view is not obliquely rotated the box geometry and
        // its extent are equalivalent so intersecting features can
        // be added directly to the collection
        const rotation = map.getView().getRotation();
        const oblique = rotation % (Math.PI / 2) !== 0;

        // when the view is obliquely rotated the box extent will
        // exceed its geometry so both the box and the candidate
        // feature geometries are rotated around a common anchor
        // to confirm that, with the box geometry aligned with its
        // extent, the geometries intersect
        if (oblique) {
          const anchor = [0, 0];
          const geometry = dragBox.getGeometry().clone();
          geometry.translate(-world * worldWidth, 0);
          geometry.rotate(-rotation, anchor);
          const extent = geometry.getExtent();
          boxFeatures.forEach(function (feature) {
            const geometry = feature.getGeometry().clone();
            geometry.rotate(-rotation, anchor);
            if (geometry.intersectsExtent(extent)) {
              select.selectFeature(feature);
            }
          });
        } else {
          boxFeatures.forEach(select.selectFeature.bind(select));
        }
      }
    });

    // clear selection when drawing a new box and when clicking on the map
    dragBox.on('boxstart', function () {
      select.clearSelection();
    });

    const infoBox = document.getElementById('info');

    select.on('select', function () {
      const names = select
        .getFeatures()
        .getArray()
        .map((feature) => {
          return feature.get('ECO_NAME');
        });
      if (names.length > 0) {
        infoBox.innerHTML = names.join(', ');
      } else {
        infoBox.innerHTML = 'None';
      }
    });

##### index.html

    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8">
        <title>Box Selection</title>
        <link rel="stylesheet" href="node_modules/ol/ol.css">
        <style>
          .map {
            width: 100%;
            height: 400px;
          }
        </style>
      </head>
      <body>
        <div id="map" class="map"></div>
        <div>Selected regions: <span id="info">None</span></div>

        <script type="module" src="main.js"></script>
      </body>
    </html>

##### package.json

    {
      "name": "box-selection",
      "dependencies": {
        "ol": "10.9.0"
      },
      "devDependencies": {
        "vite": "^3.2.3"
      },
      "scripts": {
        "start": "vite",
        "build": "vite build"
      }
    }