WFSLayerView

const query = csvLayerView.createQuery();
query.where = "magnitude > 4";
csvLayerView.queryFeatures(query).then(function(results) {
  console.log(results);
})
.catch(function(error) {
  console.log(error);
});

// highlight features based on a query result
let highlight;
view.whenLayerView(treesLayer).then(function(layerView){
  layerView.highlightOptions = {
    color: "#FF00FF", //bright fuchsia
    haloOpacity: 0.8,
    fillOpacity: 0.3
  };
  let query = treesLayer.createQuery();
  query.where = "type = 'Quercus'";
  treesLayer.queryFeatures(query).then(function(result){
    highlight?.remove();
    highlight = layerView.highlight(result.features);
  });
});

// highlight feature on pointer-move
view.on("pointer-move", function(event){
  view.hitTest(event).then(function(response){
    if (response.results.length) {
      let graphic = response.results.filter(function (result) {
        return result.graphic.layer === treesLayer;
      })[0].graphic;

     view.whenLayerView(graphic.layer).then(function(layerView){
       layerView.highlight(graphic);
     });
    }
  });
});

// clustered point layer
const layer = new FeatureLayer({
  featureReduction: { type: "cluster" }
});

const layerView = await view.whenLayerView(layer);
await reactiveUtils.whenOnce(() => !layerView.updating);

// features represents all the clusters in the view
const { features } = await layerView.queryAggregates();

let layer = new CSVLayer({
  url: csvUrl  // URL to a csv file
});

const layerView = await view.whenLayerView(layer);
await reactiveUtils.whenOnce(() => !layerView.updating);

const results = await layerView.queryExtent()
view.goTo(results.extent);  // go to the extent of all the graphics in the layerView

// Expand the extent so that a feature (i.e. point feature)
// won't be off screen after the end of goTo animation.
const { extent } = await layerView.queryExtent()
const zoomScale = 16000;
extent.expand((zoomScale / view.scale) * view.resolution);
view.goTo(extent);

view.on("click", (event) => {
  let query = new Query();
  query.geometry = event.mapPoint;  // obtained from a view click event
  query.spatialRelationship = "intersects";

  const layerView = await view.whenLayerView(layer);
  await reactiveUtils.whenOnce(() => !layerView.updating);

  const count = await layerView.queryFeatureCount(query);
  console.log(count);  // prints the number of the client-side graphics that satisfy the query
});

const layerView = await view.whenLayerView(layer);
const count = await layerView.queryFeatureCount()
console.log(count);  // prints the total number of client-side graphics to the console

let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

let query = new Query();
query.geometry = new Extent({
 xmin: -9177811,
 ymin: 4247000,
 xmax: -9176791,
 ymax: 4247784,
 spatialReference: 102100
});
query.spatialRelationship = "intersects";

const layerView = await view.whenLayerView(layer);
await reactiveUtils.whenOnce(() => !layerView.updating);

const results = await layerView.queryFeatures(query);
console.log(results.features);  // prints the array of client-side graphics to the console

let layer = new FeatureLayer({
  url: fsUrl  // points to a Feature Service layer url
});

// returns all the graphics from the layerView
const layerView = await view.whenLayerView(layer);
await reactiveUtils.whenOnce(() => !layerView.updating);

const results = await layerView.queryFeatures()
console.log(results.features); // prints all the client-side graphics to the console

layerView.queryFeatures({
  geometry: mapPoint,
  // 6 pixels around a point at the view resolution to query around a finger.
  distance: view.resolution * 6,
});

view.on("click", async (event) => {
  let query = new Query();
  query.geometry = event.mapPoint;  // obtained from a view click event
  query.spatialRelationship = "intersects";

  const layerView = await view.whenLayerView(layer)
  await reactiveUtils.whenOnce(() => !layerView.updating);

  const ids = await layerView.queryObjectIds(query);
  console.log(ids);  // prints the ids of the client-side graphics to the console=
});

// returns all the Ids from the graphics in the layerView
view.whenLayerView(layer).then(function(layerView){
  return layerView.queryObjectIds()
}).then(function(ids){
  console.log(ids);  // prints the ids of all the client-side graphics to the console
});