MediatR VS deno

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.

NodeJS is the dominant Javascript server runtime environment for Javascript and Typescript (sort of) projects. But over the years, we have seen several attempts to build alternative runtime environments such as Deno and Bun, today’s subject, among others.

https://github.com/denoland/deno/issues is the ideal place -- we try to triage all incoming issues, the more specific the repro the easier it is to address but we will take a look at everything that comes in.

Install Node.js (or Bun, or Deno, or whatever JS runtime you prefer) if it's not there

QUIC is very exciting, after seeing what it can do for performance in Cloudflare network and Cloudflare workers, I can't wait to finally see it in Deno[0] 1.41.

[0] https://github.com/denoland/deno/pull/21942#issuecomment-192...

So as an end user it's kind of like https://deno.com/ where you buy into a runtime + comes prepacked with DBs (k/v stores), scheduling, and deploy stuff?

> by storing Unison code in a database, keyed by the hash of that code, we gain a perfect incremental compilation cache which is shared among all developers of a project. This is an absolutely WILD feature, but it's fantastic and hard to go back once you've experienced it. I am basically never waiting around for my code to compile - once code has been parsed and typechecked once, by anyone, it's not touched again until it's changed.

Interesting. Whats it like upgrading and managing dependencies in that code? I'd assume it gets more complex when it's not just the Union system but 3rd party plugins (stuff interacting with the OS or other libs).

~90MB+ at this stage and do now allow compression without erroring out. Deploying ala Golang is not feasible at that level but could well be down the line if this dev branch is picked up again!

The exe output grew from from ~50MB to plus ~90MB from 2021 to 2024: https://github.com/denoland/deno/discussions/9811 which mean Deno is worse than Node.js's pkg solution by a decent margin.

Behind the scenes is a simple Sveltekit-powered server function to fetch a Spotify client token then find a user's recommendation playlist and its track information. A Deno edge function to performs this data fetch and renders server-side Svelte.

If your application is written in JavaScript, integrating it with JavaScript extensions is a no-brainer. However, Secutils.dev is entirely written in Rust. How would I even begin? Fortunately, I recently came across an excellent blog post series explaining how to implement your JavaScript runtime in a Rust application with Deno: