This example uses OpenLayers v10.9.0. The latest is v.
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#### Select Features

select 4 vector 86

#####

Action type
0 selected features

Example of using the Select interaction.

Choose between `Single-click`, `Click`, `Hover` and `Alt+Click` as the event type for selection in the combobox below. When using `Single-click` or `Click` you can hold the `Shift` key to toggle the feature in the selection.

Note: when `Single-click` is used double-clicks won't select features. This in contrast to `Click`, where a double-click will both select the feature and zoom the map (because of the `DoubleClickZoom` interaction). Note that `Single-click` is less responsive than `Click` because of the delay it uses to detect double-clicks.

In this example, a listener is registered for the Select interaction's `select` event in order to update the selection status above.

##### main.js

    import Map from 'ol/Map.js';
    import View from 'ol/View.js';
    import {altKeyOnly, click, never, pointerMove} from 'ol/events/condition.js';
    import GeoJSON from 'ol/format/GeoJSON.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 style = new Style({
      fill: new Fill({
        color: '#eeeeee',
      }),
    });

    const vector = new VectorLayer({
      source: new VectorSource({
        url: 'https://openlayers.org/data/vector/ecoregions.json',
        format: new GeoJSON(),
      }),
      background: 'white',
      style: function (feature) {
        const color = feature.get('COLOR') || '#eeeeee';
        style.getFill().setColor(color);
        return style;
      },
    });

    const map = new Map({
      layers: [vector],
      target: 'map',
      view: new View({
        center: [0, 0],
        zoom: 2,
      }),
    });

    let select = null; // ref to currently selected interaction

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

    function selectStyle(feature) {
      const color = feature.get('COLOR') || '#eeeeee';
      selected.getFill().setColor(color);
      return selected;
    }

    // select interaction working on "singleclick"
    const selectSingleClick = new Select({style: selectStyle});

    // select interaction working on "click"
    const selectClick = new Select({
      condition: click,
      style: selectStyle,
    });

    // select interaction working on "pointermove"
    const selectPointerMove = new Select({
      condition: pointerMove,
      toggleCondition: never, // otherwise the move events cause the features to flicker when holding shift
      style: selectStyle,
    });

    const selectAltClick = new Select({
      style: selectStyle,
      condition: function (mapBrowserEvent) {
        return click(mapBrowserEvent) && altKeyOnly(mapBrowserEvent);
      },
    });

    const selectElement = document.getElementById('type');

    const changeInteraction = function () {
      if (select !== null) {
        map.removeInteraction(select);
      }
      const value = selectElement.value;
      if (value == 'singleclick') {
        select = selectSingleClick;
      } else if (value == 'click') {
        select = selectClick;
      } else if (value == 'pointermove') {
        select = selectPointerMove;
      } else if (value == 'altclick') {
        select = selectAltClick;
      } else {
        select = null;
      }
      if (select !== null) {
        map.addInteraction(select);
        select.on('select', function (e) {
          document.getElementById('status').innerHTML =
            '&nbsp;' +
            e.target.getFeatures().getLength() +
            ' selected features (last operation selected ' +
            e.selected.length +
            ' and deselected ' +
            e.deselected.length +
            ' features)';
        });
      }
    };

    /**
     * onchange callback on the select element.
     */
    selectElement.onchange = changeInteraction;
    changeInteraction();

##### index.html

    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8">
        <title>Select Features</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>
        <form>
          <label for="type">Action type &nbsp;</label>
          <select id="type">
            <option value="click" selected>Click</option>
            <option value="singleclick">Single-click</option>
            <option value="pointermove">Hover</option>
            <option value="altclick">Alt+Click</option>
            <option value="none">None</option>
          </select>
          <span id="status">&nbsp;0 selected features</span>
        </form>

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

##### package.json

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