Should I use IJsInProcessRuntime or [JSImport] API for "regular javascript interop calls?

[Matheos96]

We just migrated our .NET 6 code base to .NET 8 and I am familiarizing myself with what we can do in blazor with the new additions from .NET 7 and 8. We are running Blazor WASM Standalone btw.

Earlier we used IJsInProcessRuntime and IJsUnmarshalledRuntime (or whatever it is called). The latter is now deprecated in .NET 7 and we have been blessed with the new [JSImport]/[JSExport] API. My question is, since IJSInProcessRuntime is not deprecated, which one is the better option, JSImport or IJsInProcessRuntime? Performance wise. One thing I have noticed is that I don't think we can call functions on JS classes using JSImport, like we can with IJsInProcessRuntime and a JSObjectReference.

Again, we are on WASM only, so we can use sync only calls as much as possible

[javiercn]

IJsInProcessRuntime is the only thing officially supported by Blazor. If you rely on [JSImport] and [JSExport] it's not guaranteed that some Blazor features work. That said, if you want the maximum performance (in 99% of the cases you don't need it) [JSImport] and [JSExport] are the way to go.

[javiercn]

I don't know for sure, but likely the answer is no, features like IJSObjectReference won't work with JSImport/Export

[javiercn]

And that [JSImport] and [JSExport] won't work with Blazor Server.

[Matheos96]

Okay yes, then we are on the same page. We are on wasm only so that is no issue, but I was wondering a bit regarding IJSobjectreference. So at least I cannot call "instance" methods using a IJSObjectreference and JSImport, but can I pass the object itself through JSImport and call methods on the JS side?

[javiercn]

So at least I cannot call "instance" methods using a IJSObjectreference and JSImport, but can I pass the object itself through JSImport and call methods on the JS side?

I don't believe so. I think that [JSImport] and [JSExport] have their own way of achieving that.

[Matheos96]

Okay, I guess I will just have to give it a try. Thanks for the info! The documentation overall regarding the JSImport stuff is not too well covered in my opinion. Yes, we have the official docs but it is not too in depth with actual use case scenarios.