Improved TypeScript development with ArcGIS API for JavaScript

The TypeScript declaration file for the ArcGIS API for JavaScript contains type information specific for the API. You can learn more about how to install this file from the TypeScript set up guide page or on GitHub.

The version 4.6 introduces several improvements:

The documentation also includes a link to directly open the API reference at the relevant page.

const map = new WebMap({
  // autocasts to a Basemap object
  basemap: "topo",
  layers: [
    new FeatureLayer({
      // autocasts to a PopupTemplate object
      popupTemplate: {
        content: "{*}"
      }
    })
  ]
});

const symbol = new SimpleFillSymbol({
  // autocasts to a Color object
  color: "red",
  // autocasts to a SimpleLineSymbol object
  outline: {
    style: "solid"
  }
});

import { Geometry } from "esri/geometry";

function logGeometry(geometry: geometry): void {
  // Geometry is a union of all the geometries
  // discriminate on the 'type' property
  if (geometry.type === "point") {
    // new at 4.6, the compiler knows the geometry is a Point instance
    console.log("point coords: ", geometry.x, geometry.y, geometry.z);
  }
  else {
    // the compiler knows the geometry must be a `Extent | Polygon | Multipoint | Polyline`
    console.log("The value is a geometry, but isn't a point.")
  }
}

We hope these improvements will make you more productive in your application development.