// Note: this logic is wrapped up in a package you can use here:
// https://www.npmjs.com/package/query-all-features
// 
// demo here: https://codepen.io/gavinr/pen/ExQYegd?editors=0010
//
// More info: https://gavinr.com/arcgis-javascript-query-all-features/
//
require(["esri/layers/FeatureLayer"], function (
  FeatureLayer
) {
  
  // The "public" function that can be called by passing a reference to the
  // layer. Only provided so the "user" of this module (you) does not have to rememeber
  // to pass [] as the second parameter to the recursive function.
  const getAllFeatures = (layer) => {
    return _getAllFeaturesRecursive(layer, []);
  };

  // Recursive function - Handles calling the service multiple times if necessary.
  const _getAllFeaturesRecursive = (layer, featuresSoFar) => {
    console.log("got features:", featuresSoFar.length);

    return layer
      .queryFeatures({
        start: featuresSoFar.length,
        num: layer.capabilities.query.maxRecordCount,
        // where: "st = 'CA'",
        outFields: ['*']
      })
      .then((results) => {
      // If "exceededTransferLimit" is true, then make another request (call 
      //  this same function) with a new "start" position. If not, we're at the end
      // and we should just concatenate the results and return what we have.
        if (
          results.exceededTransferLimit &&
          results.exceededTransferLimit === true
        ) {
          return _getAllFeaturesRecursive(layer, [
            ...featuresSoFar,
            ...results.features
          ]);
        } else {
          return Promise.resolve([...featuresSoFar, ...results.features]);
        }
      });
  };

  const featureLayer = new FeatureLayer({
    url:
      "https://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer/0"
  });

  // We're calling `.when()` and `.load()` below because the layer is not being loaded in a Map and 
  // MapView --
  // Most likely your app is using Map and MapView/SceneView.when(), so you can ignore that and simply:
  //
  // 1. Copy the above functions (getAllFeatures and _getAllFeaturesRecursive) into your app
  // 2. Call: getAllFeatures(featureLayer).then((results) => { ... });
  //
  featureLayer.when(() => {
    getAllFeatures(featureLayer).then((results) => {
      console.log('results', results);
      document.getElementById('results').innerHTML = `${results.length} results: <br /><br />` +  JSON.stringify(results, null, 4);
    });
  });
  featureLayer.load();
});