Blazor What's New and Migration guidance

[guardrex]

Addresses #26364

Ready! ... but let me try to reach ⚔️ Sir Artak 🛡️ and ⚔️ Sir Dan 🛡️ of .NETtingham 🏰 to see if they'd like to look before merging. If I don't get a response soon (1pm CST), I'll merge and circle around later with them.

Dan, Artak ...

• Some of the commented-out content is IN PROGRESS stuff. I'll activate it later.
• Some of it is on HOLD because I'm not sure we would call them out. I'm 👂 if you see some of them that I should activate. If not, I'm going to 🔪 the HOLD ones later.

UPDATE

Review in progress. We should have this merged this merged in a few hours.

[guardrex]

It's expensive 💰 ... describing every template change step-by-step? I did that once before. It took hours to write out.

[guardrex]

Let me check again on the migration guidance: Do you want every template change explained for migration? I did it back for 3.1 to 5.0. Starting with this ....... but then also the sections that follow it ...........

https://learn.microsoft.com/en-us/aspnet/core/migration/31-to-50?view=aspnetcore-6.0&tabs=visual-studio#update-blazor-webassembly-and-blazor-server-projects

It took quite a while ... hours 😅. I can do it. I just want to make sure before I spend the treasure on it 💰.

[danroth27]

Let me check again on the migration guidance: Do you want every template change explained for migration? I did it back for 3.1 to 5.0. Starting with this ....... but then also the sections that follow it ...........

https://learn.microsoft.com/en-us/aspnet/core/migration/31-to-50?view=aspnetcore-6.0&tabs=visual-studio#update-blazor-webassembly-and-blazor-server-projects

It took quite a while ... hours 😅. I can do it. I just want to make sure before I spend the treasure on it 💰.

Nope, I changed my mind. Let's stick with what you've got. No need to document every template change.

[guardrex]

All good thus far? It's best to merge this so that we don't block updates from the other doc cats.

I placed notes for the couple of items that need more work. I'll get on those Monday/Tuesday.

BTW on the JS interop PR ... I'm still waiting on Pavel to get back to me. I thought I'd get his technical review feedback first, but I suppose you could see if (based on your feedback) it could be merged. On the other hand, release isn't like tomorrow! 🏃:smile: It seems like it could wait a bit longer for him to respond there.

[guardrex]

Is it ok now?

I'm going to crash ... the 🐱 alarm jumped on me at 3AM this morning. I'm toast. 🛌💤

[mkArtakMSFT]

Thanks @guardrex !

[guardrex]

Updates made, and I think we might want to add a migration item for @bind:get/@bind:set because that cleans up get/set accessor syntax nicely in multiple component binding scenarios. Therefore, I placed a smidgen of binding modifier coverage in the Migration article with cross-links.

[guardrex]

I've also fleshed out our WASM build tools coverage for .NET 7 or later with the following on SIMD and WASM exception handling.

This content is live now in the Tooling article, and the What's New content links to it. I'll patch the following as needed. You can send me a message here on what to patch.

When [Ahead-of-time (AOT) compilation](xref:blazor/host-and-deploy/webassembly#ahead-of-time-aot-compilation) is used, [WebAssembly Single Instruction, Multiple Data (SIMD)](https://github.com/WebAssembly/simd/blob/master/proposals/simd/SIMD.md) is supported, **except for Apple Safari at this time**. Use the `<WasmEnableSIMD>` property in the app's project file (`.csproj`) with a value of `true`:

```xml
<PropertyGroup>
  <WasmEnableSIMD>true</WasmEnableSIMD>
  <RunAOTCompilation>true</RunAOTCompilation>
</PropertyGroup>
```

To enable WebAssembly exception handling, use the `<WasmEnableExceptionHandling>` property in the app's project file (`.csproj`) with a value of `true`:

```xml
<PropertyGroup>
  <WasmEnableExceptionHandling>true</WasmEnableExceptionHandling>
</PropertyGroup>
```

[danroth27]

LGTM