topic Re: ArcGIS JS API & TypeScript & Visual Studio 2015 in ArcGIS JavaScript Maps SDK Questions

ArcGIS JS API & TypeScript & Visual Studio 2015

KarenLai — Mon, 31 Jul 2017 19:13:08 GMT

Hello, I'm using Visual Studio 2015 to try to create a widget for a web application and I'm having trouble getting started. I'm following the tutorial on the ArcGIS API for JavaScript website: TypeScript - Setting up your development environment | ArcGIS API for JavaScript 4.4 , but I get red squiggles under all the properties, causing the application to not compile. I think I installed the ArcGIS Typing correctly via npm. An image is attached. Any assistance would be greatly appreciated. Thank you.

Re: ArcGIS JS API & TypeScript & Visual Studio 2015

ThomasSolow — Mon, 31 Jul 2017 19:19:57 GMT

What is the error? I'm not familiar with visual studio, but can you mouse over the underlined code to display the error?

Re: ArcGIS JS API & TypeScript & Visual Studio 2015

KarenLai — Mon, 31 Jul 2017 19:30:28 GMT

Thanks for taking a look, Thomas. The attached image shows the error list.

Re: ArcGIS JS API & TypeScript & Visual Studio 2015

ThomasSolow — Sat, 11 Dec 2021 22:25:52 GMT

I'm not completely sure that this is the issue, but I think this may have to do with how the JS API typings work with "autocasting." The signature for the basemap property is not string, it looks like:

interface BasemapProperties extends LoadableProperties {
  baseLayers?: Collection;
  id?: string;
  loaded?: boolean;
  portalItem?: PortalItemProperties;
  referenceLayers?: Collection;
  thumbnailUrl?: string;
  title?: string;
}‍‍‍‍‍‍‍‍‍

This means that although a string is valid for a basemap in javascript, it's not valid in typescript. This issue discusses some workarounds: Typings for basemap not matching actual javascript · Issue #77 · Esri/jsapi-resources · GitHub

You could try passing in { id: "streets" } to the basemap property. It may accept that. You could also try one of the workarounds in that github issue.

Re: ArcGIS JS API & TypeScript & Visual Studio 2015

KarenLai — Mon, 31 Jul 2017 21:57:13 GMT

Thank you, Thomas! The squiggles are all gone and the application compiled successfully. This is a good start. Thank you for your time!