Fixed TS issues when used with single-spa-react

[alexislucas-toast]

Description

Hi there! 👋

For a private project, we're using the single-spa-react package, and wanted to use this new helper package to not have to reproduce the logic to mount a parcel. It's working as expected, but as we are using Typescript for this project, it is complaining that the definitions for domElementGetter between single-spa-react and dom-element-getter-helpers don't match. For reference, here's the definition from single-spa-react. I think the React ecosystem is the only one that passes props to this function.

Since the domElementGetter now takes an optional props parameter, it should still work as expected for other ecosystems that don't pass it. We've tested it in our project and the Typescript issue has disappeared.

All the tests are passing, there's no formatting issue and the project builds successfully.

Also, thank you for single-spa and all the helpers, it's awesome!

Changes

• Updated domElementGetter function to take optional props

[joeldenning]

Thanks for the clear description and for contributing a fix. I've left a comment below that I think will make dom-element-getter-helpers and single-spa-react types even better, but am not 100% about it and might have missed something. Let me know what you think.

[joeldenning]

Hmm I think this should be more than just the extra props - also the AppProps. This is because the single-spa props get merged with the extra props to form the final props.

Suggested change

	domElementGetter?(props?: ExtraProps): HTMLElement;
	domElementGetter?(props?: ExtraProps & AppProps): HTMLElement;

See code below for AppProps.

https://github.com/single-spa/single-spa/blob/e63af429ad676fa2468af08b076ee154ebaa42be/typings/single-spa.d.ts#L12

Looking at the single-spa-react types, I'm not sure it's doing that part correct either, with RootComponentProps not including the sinlge-spa AppProps. So it's possible that updating the code in dom-element-getter-helpers to use AppProps causes issues with single-spa-react, in which case I think I'd prefer trying to fix both places.