RegEx101 VS MediatR

> I wonder if this could be used to make C# webassembly more viable.

You might enjoy reading this GitHub thread [0] where the community contributed a WASM library wrapping the C# regex code so that regex101.com could have a "C# mode". Lots of nerd sniping about reducing the payload size.

(There's also another thread [1] discussing the minification of a rust version of that same regex101 wasm library to provide a "rust mode" using @burntsushi's regex crate.)

[0]: https://github.com/firasdib/Regex101/issues/156

[1]: https://github.com/firasdib/Regex101/issues/1208

That’s correct, compiled to WASM. You can see all the nitty gritty here https://github.com/firasdib/Regex101/issues/1208

Excellent comparisons. ~150KB without unicode would make Rust the smallest wasm on Regex101 as far as I can tell. pcrelib comes in at 198KB. Personally, I think ~400KB with unicode features is just fine for .wasm size. The heaviest flavor C# is around 4.91MB and was added back in February of this year. They also had a performance comparison which would also be interesting.

You probably noticed that .SetName() returns a Either. You may have come across Unit in libraries like MediatR or Language-Ext. It's a simple construct representing a type with only one possible value. We use it as a placeholder for operations that do not return a value but may return another state. In our example, .SetName() is a Command that does not return a value but may fail. Therefore, the monad Either carries two possible states: Right (without value) or Left (with an Error).

The widely used MediatR library[0] could be used to do that as well, just FYI.

[0]: https://github.com/jbogard/MediatR

Hope this GH issue shed some light on why injecting handler inside another handler is not good https://github.com/jbogard/MediatR/issues/400

From: https://github.com/jbogard/MediatR

I gave it a go and I was impressed how easy and fast it was to set it all up. Since I'm not a big fan of REPR pattern almost all my projects are using CQRS pattern with a help of MediatR ](https://github.com/jbogard/MediatR) I immediately started going over something similar that Fast Endpoints offer which is a command bus.

I'd use a dedicated event bus based on Reactive Extensions or MediatR to publish domain events from your domain services. This probably doesn't solve all your ViewModel update problems as is, maybe you need to revise the granularity (maybe you can have smaller ViewModels that refresh single property that exposes the Model) and lifespan (sometimes you can create a ViewModel, make it perform it's task and then discard it completely) of your ViewModels.

If you're finding yourself in a situation where you need to turn this behavior into a pattern because there are a lot of View Models that need to execute async business logic in response to some changes, I'd go with something like MediatR or Reactive Extensions. The idea is, again, that some other, probably business-level, component listens to changes in a decoupled way (that means it doesn't subscribe directly to your View Model, but to an event bus instead). View Model publishes change events to the event bus, and business-component reacts to these events by executing the business logic.

What people really want is to design the logic of an app independently from the component hierarchy. That means you need to store state somewhere other than the components and you need to dispatch events that are not attached to the component hierarchy. Also, a one way data flow has well known benefits as described by things like CQRS, RabbitMQ, and MediatR.