Openlayers WMS-GetFeatureInfoUrl不是函数

我有一个wms图层，它在地图上显示得很好，但是当我试图在单击图层时从该图层获取对象时，我得到一个错误GetFeatureInfoUrl不是一个函数

    var wmsSource = new TileWMS({
      url: 'http://1.1.1.1:8080/geoserver/wms',
      params: {'LAYERS': 'workspace:feature', 'TILED': true},
      serverType: 'geoserver',
      transition: 0,
    });
    var wmsLayer = new TileLayer({
      source: wmsSource
    })
    var view = new View({
      center: [0, 0],
      zoom: 1,
    });
    if (checked) {
        map.addLayer(wmsLayer);
  }
    else {
      map.removeLayer(wmsLayer)
  }

  map.on('singleclick', function (evt) {
    var viewResolution = /** @type {number} */ (view.getResolution());
    var feature = wmsSource.getGetFeatureInfoUrl(
      evt['coordinate'],
      viewResolution,
      'EPSG:3857',
      {'INFO_FORMAT': 'text/html'}
    );
    if (feature) {
      fetch(feature)
        .then(function (response) { return response.text(); })
        .then(function (info) {
         console.log(info);
          
        });
    }

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我可以用它做什么？

解决方案是从以下层获取源代码：

map.on('singleclick', function (evt) {
    var viewResolution = /** @type {number} */ (view.getResolution());
    var feature = wmsLayer.getSource().getFeatureInfoUrl(
      evt['coordinate'],
      viewResolution,
      'EPSG:3857',
      {'INFO_FORMAT': 'text/html'}
    );
    if (feature) {
      fetch(feature)
        .then(function (response) { return response.text(); })
        .then(function (info) {
         console.log(info);
          
        });
    }

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如果使用OpenLayers 6，函数名为getFeatureInfoUrl我不知道为什么OpenLayers建议我只使用getFeatureInfoUrl，getFeatureInfoUrl不可用。OpenLayers 6.4.3请参阅升级说明“将getFeatureInfoUrl重命名为getFeatureInfoUrl”