topic Re: Unable to override fetchTile() in WebTileLayer.createSubclass in ArcGIS JavaScript Maps SDK Questions

Unable to override fetchTile() in WebTileLayer.createSubclass

AriefAbuBakar — Wed, 14 Dec 2022 07:13:52 GMT

Hi, I can no longer override fetchTile() in WebTileLayer.createSubclass() after I upgrade the ES module from version 4.24.* to version 4.25.*. It is no longer call the fetchTile() function. I tried the CDN version from https://js.arcgis.com/4.25/ but its working fine

Re: Unable to override fetchTile() in WebTileLayer.createSubclass

AndyGup — Wed, 14 Dec 2022 19:16:27 GMT

Hi @AriefAbuBakar it's very possible that your code was working accidentally. You need to use the "extends" keyword when building subclasses with ES modules: https://developers.arcgis.com/javascript/latest/implementing-accessor/#create-a-simple-subclass. It can be challenging when overriding API functionality because properties, methods and patterns within the underlying API Class are subject to change.

// Psuedo-example using @arcgis/core ES modules class ExampleWebTileLayer extends WebTileLayer { constructor(properties?:any) { super(properties); } . . . }

Re: Unable to override fetchTile() in WebTileLayer.createSubclass

AndyGup — Wed, 14 Dec 2022 23:22:48 GMT

Update - this looks like a regression at 4.25, thanks for reporting. We've opened an issue to fix it.

Re: Unable to override fetchTile() in WebTileLayer.createSubclass

YannCabon — Thu, 15 Dec 2022 17:20:45 GMT

Like @AndyGup said, it's a regression. If you override `fetchTile()` I'd suggest to extend `BaseTileLayer` https://developers.arcgis.com/javascript/latest/api-reference/esri-layers-BaseTileLayer.html which is better suited for extensibility.

Re: Unable to override fetchTile() in WebTileLayer.createSubclass

AndyGup — Fri, 17 Feb 2023 00:53:09 GMT

@AriefAbuBakarthis is now fixed and will be available at 4.26. You can test it today by installing the latest 'next' build:

npm i @arcgis/core@next