Thinning

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        pointsLayer.featureReduction = {
          type: "selection"
        };

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        const highwaysLayer = new FeatureLayer({
          portalItem: {
            id: "af989f50f24040e4890dce13ee1b1561"
          },
          minScale: 1000000,
          maxScale: 0
        });

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        const levels = [{
          minScale: Infinity,
          maxScale: 150000,
          definitionExpression: "highway IN ('motorway')"
        }, {
          minScale: 150000,
          maxScale: 60000,
          definitionExpression: "highway IN ('motorway', 'trunk', 'trunk_link')"
        }, {
          minScale: 60000,
          maxScale: 45000,
          definitionExpression: "highway IN ('motorway', 'motorway_link', 'trunk', 'trunk_link', 'primary', 'primary_link')"
        }, {
          minScale: 45000,
          maxScale: 30000,
          definitionExpression: "highway IN ('motorway', 'motorway_link', 'trunk', 'trunk_link', 'primary', 'primary_link')"
        }, {
          minScale: 30000,
          maxScale: 10000,
          definitionExpression: "highway IN ('motorway', 'motorway_link', 'trunk', 'trunk_link', 'primary', 'primary_link', 'secondary', 'secondary_link')"
        }];

        // Update the definition expression based on view scale
        view.watch("scale", function(scale){
          let definitionExpression = null;
          const level = levels.find(
            level =>
            scale < level.minScale && scale >= level.maxScale
          );

          if(level){
            definitionExpression = level.definitionExpression;
          }
          if(definitionExpression !== highwaysLayer.definitionExpression){
            highwaysLayer.definitionExpression = definitionExpression;
          }
        });