openlayers根据图层名称判断图层是否在视口内

openlayers根据图层名称判断图层是否在视口内

/*** 判断图层是否在视口内* @param {*} map* @param {*} layername 图层名称* @returns*/judgeLayerIsInViewport(map, layername) {var layers = map.getLayers().getArray()const viewExtent = map.getView().calculateExtent(map.getSize())for (let index = 0; index < layers.length; index++) {const layer = layers[index]if (layer.get('name') == layername) {const layerExtent = layer.getSource().getExtent() if (!layerExtent) return false const isIn = intersects(viewExtent, layerExtent)return isIn}}}