This example uses OpenLayers v10.9.0. The latest is v.
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#### Custom Drag-and-Drop (MVT preview)

drag-and-drop 3 mvt 1

#####

Tile coordinate z: x: y:

Example of using the drag-and-drop interaction with a custom format to preview MVT tiles.

Example of using the drag-and-drop interaction with a custom format to preview MVT tiles. In addition to the formats used in the Drag-and-Drop example individual MVT tiles can be previewed. There is no projection transform support, so this will only work with data in EPSG:4326 and EPSG:3857.

##### main.js

    import Feature from 'ol/Feature.js';
    import Map from 'ol/Map.js';
    import View from 'ol/View.js';
    import GPX from 'ol/format/GPX.js';
    import GeoJSON from 'ol/format/GeoJSON.js';
    import IGC from 'ol/format/IGC.js';
    import KML from 'ol/format/KML.js';
    import MVT from 'ol/format/MVT.js';
    import TopoJSON from 'ol/format/TopoJSON.js';
    import DragAndDrop from 'ol/interaction/DragAndDrop.js';
    import {defaults as defaultInteractions} from 'ol/interaction/defaults.js';
    import TileLayer from 'ol/layer/Tile.js';
    import VectorLayer from 'ol/layer/Vector.js';
    import OSM from 'ol/source/OSM.js';
    import VectorSource from 'ol/source/Vector.js';
    import {createXYZ} from 'ol/tilegrid.js';

    // Define a custom MVT format as ol/format/MVT requires an extent

    const tileCoordZ = document.getElementById('tileCoordZ');
    const tileCoordX = document.getElementById('tileCoordX');
    const tileCoordY = document.getElementById('tileCoordY');

    class customMVT extends MVT {
      constructor() {
        super({featureClass: Feature});
      }
      readFeatures(source, options) {
        options.extent = createXYZ().getTileCoordExtent([
          parseInt(tileCoordZ.value),
          parseInt(tileCoordX.value),
          parseInt(tileCoordY.value),
        ]);
        return super.readFeatures(source, options);
      }
    }

    // Set up map with Drag and Drop interaction

    const dragAndDropInteraction = new DragAndDrop({
      formatConstructors: [customMVT, GPX, GeoJSON, IGC, KML, TopoJSON],
    });

    const map = new Map({
      interactions: defaultInteractions().extend([dragAndDropInteraction]),
      layers: [
        new TileLayer({
          source: new OSM(),
        }),
      ],
      target: 'map',
      view: new View({
        center: [0, 0],
        zoom: 2,
      }),
    });

    dragAndDropInteraction.on('addfeatures', function (event) {
      const vectorSource = new VectorSource({
        features: event.features,
      });
      map.addLayer(
        new VectorLayer({
          source: vectorSource,
        }),
      );
      map.getView().fit(vectorSource.getExtent());
    });

    const displayFeatureInfo = function (pixel) {
      const features = [];
      map.forEachFeatureAtPixel(pixel, function (feature) {
        features.push(feature);
      });
      if (features.length > 0) {
        const info = [];
        let i, ii;
        for (i = 0, ii = features.length; i < ii; ++i) {
          const description =
            features[i].get('name') ||
            features[i].get('_name') ||
            features[i].get('layer');
          if (description) {
            info.push(description);
          }
        }
        document.getElementById('info').innerHTML = info.join(', ') || '&nbsp';
      } else {
        document.getElementById('info').innerHTML = '&nbsp;';
      }
    };

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

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

    // Sample data download

    const link = document.getElementById('download');

    function download(fullpath, filename) {
      fetch(fullpath)
        .then(function (response) {
          return response.blob();
        })
        .then(function (blob) {
          link.href = URL.createObjectURL(blob);
          link.download = filename;
          link.click();
        });
    }

    document.getElementById('download-mvt').addEventListener('click', function () {
      const fullpath =
        'https://basemaps.arcgis.com/arcgis/rest/services/World_Basemap_v2/VectorTileServer/tile/' +
        tileCoordZ.value +
        '/' +
        tileCoordY.value +
        '/' +
        tileCoordX.value +
        '.pbf';
      const filename =
        tileCoordZ.value + '-' + tileCoordX.value + '-' + tileCoordY.value + '.mvt';
      download(fullpath, filename);
    });

##### index.html

    <!DOCTYPE html>
    <html lang="en">
      <head>
        <meta charset="UTF-8">
        <title>Custom Drag-and-Drop (MVT preview)</title>
        <link rel="stylesheet" href="node_modules/ol/ol.css">
        <style>
          .map {
            width: 100%;
            height: 400px;
          }
          .tileCoord input {
            width: 60px;
          }
        </style>
      </head>
      <body>
        <div id="map" class="map"></div>
        <br />
        <div class="tileCoord">
          <a id="download" download></a>
          <span>Tile coordinate&nbsp;&nbsp;</span>
          <span>&nbsp;z: <input type="number" id="tileCoordZ" value="6" /></span>
          <span>&nbsp;x: <input type="number" id="tileCoordX" value="30" /></span>
          <span>&nbsp;y: <input type="number" id="tileCoordY" value="20" /></span>
          <span>&nbsp;&nbsp;</span>
          <button id="download-mvt">Download sample</button>
        </div>
        <br />
        <div id="info">&nbsp;</div>

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

##### package.json

    {
      "name": "drag-and-drop-custom-mvt",
      "dependencies": {
        "ol": "10.9.0"
      },
      "devDependencies": {
        "vite": "^3.2.3"
      },
      "scripts": {
        "start": "vite",
        "build": "vite build"
      }
    }