topic Re: Property "add doesn't exist in map" when trying to implment typescript with react in ArcGIS JavaScript Maps SDK Questions

Property "add doesn't exist in map" when trying to implment typescript with react

KenjooYeap — Tue, 24 Aug 2021 16:44:53 GMT

I am trying to add typescript to the react code base that I have developed. Using the type "__esri.MapView" seems to have caused the following error, when trying to do "map.add" when trying to add layers to the view:

"Property 'add' does not exist on type 'MapView | Map'. Property 'add' does not exist on type 'MapView'.

Am I using the wrong type here? Can someone point me to the right direction which type I should be using for MapView?

Thanks!

Re: Property "add doesn't exist in map" when trying to implment typescript with react

ReneRubalcava — Tue, 24 Aug 2021 16:55:19 GMT

If I understand, in your code you have something where it looks like this maybe?

function addToMap(target: MapView | Map) { // this is what you are trying to do // target.add(layer) // but you need to let TypeScript know what type it should expect. // you can do something like this, I haven't tested if (!Boolean(target.container)) { // should work because container is not on Map // but is on MapView // now TS knows what it is using target.add(layer); } }

That might help, if not, do have a reproducible sample of the issue.

Re: Property "add doesn't exist in map" when trying to implment typescript with react

KenjooYeap — Tue, 24 Aug 2021 18:41:03 GMT

Thanks for the hint, my function was returning two possible types and I have to cast it to a tuple so that it's assigned to the right type.