topic How do you expose the interfaces used in parameters to other classes in ArcGIS JavaScript Maps SDK Questions

How do you expose the interfaces used in parameters to other classes

Aeseir — Sat, 01 Apr 2023 07:53:51 GMT

I use Typescript for my application and I want to use FeatureLayerProperties to ensure whatever is put through the function, meets the bare minimum requirement for a FeatureLayer for purposes of creation.

Currently I am using a parameter:any, because paramenter:FeatureLayerProperties doesn't work, as FeatureLayerProperties is not exported by any arcgis library I have found so far.

Is there a way to expose FeatureLayerProperties to custom functions/methods/classes so that we can have strongly typed?

Re: How do you expose the interfaces used in parameters to other classes

ReneRubalcava — Sat, 01 Apr 2023 20:25:57 GMT

You can use some TS utilities to help you out here.

type FeatureLayerProp = InstanceType<typeof FeatureLayer>;

https://www.typescriptlang.org/docs/handbook/utility-types.html#instancetypetype

Re: How do you expose the interfaces used in parameters to other classes

Omar_A — Sun, 02 Apr 2023 16:00:32 GMT

HI Aeseir,

As far as I know that the FeatureLayerProperties interface is not exported by any ArcGIS library, hence, it cannot be used directly in TypeScript code. However, one workaround way to obtain strong typing is to create a custom interface that extends the FeatureLayerProperties interface and includes any additional properties or restrictions that you require for your specific use case. This custom interface can then be used as the type for your function parameter.

TypeScript: Documentation - Object Types (typescriptlang.org)

Best,

Omar

Re: How do you expose the interfaces used in parameters to other classes

Aeseir — Wed, 05 Apr 2023 09:35:47 GMT

Thanks @ReneRubalcava i actually tried that as fallback option way back but it broke a few times during runtime and stopped that using it.

Re: How do you expose the interfaces used in parameters to other classes

Aeseir — Wed, 05 Apr 2023 09:39:55 GMT

As you mentioned it is not exported, so you can't build a customer interface that extends unless it is in the file itself where FeatureLayerProperties sits. Which would get overwritten the minute you updated the arcgis sdk, then you back to square one.

Or are you implying another approach that i didn't see in that link?