proposal-explicit-resource-managemen VS maud

In addition to this, is the new (stage 3 even!)explicit resource management proposal[0], supported by TypeScript version >= 5.2[1]

Though I agree that async context is better fit for this generally, the RMP should be good for telemetry around objects that have defined lifetime semantics, which is a step in the right direction you can use today

[0]: https://github.com/tc39/proposal-explicit-resource-managemen...

[1]: https://www.totaltypescript.com/typescript-5-2-new-keyword-u...

There's a conversation I had with Ron Buckton, the proposal champion, mainly on this specific issue. [1]

Short answer: Yes, Disposable can leak if you forget "using" it. And it will leak if the Disposable is not guarded by advanced GC mechanisms like the FinalizationRegistry.

Unlike C# where it's relatively easier to utilize its GC to dispose undisposed resources [2], properly utilizing FinalizationRegistry to do the same thing in JavaScript is not that simple. In response to our conversation, Ron is proposing adding the use of FinalizationRegistry as a best practice note [3], but only for native handles. It's mainly meant for JS engine developers.

Most JS developers wrapping anything inside a Disposable would not go through the complexity of integrating with FinalizationRegistry, thus cannot gain the same level of memory-safety, and will leak if not "using" it.

IMO this design will cause a lot of problems, misuses and abuses. But making JS to look more like C# is on Microsoft's agenda so they are probably not going to change anything.

[1]: https://github.com/tc39/proposal-explicit-resource-managemen...

I'm not _entirely_ sure which RAII you mean, but if you mean something like C#'s `using` or Java's `try-with-resources` or Python's `with`, then https://github.com/tc39/proposal-explicit-resource-managemen... and https://github.com/tc39/proposal-async-explicit-resource-man... are in stage 3 (of 4 stages) in ECMAScript's language proposal lifecycle and will be coming to a JS engine near you behind a flag soon-ish.

I'd prefer something with a more sound type system, and something that makes cleaning up resources easier and more ergonomic.

This might help with cleanup: https://github.com/tc39/proposal-explicit-resource-managemen...

But I'm not sure anything will help with the type system. For example, this drives me absolutely insane: https://www.typescriptlang.org/play#code/MYewdgziA2CmB00QHMA...

There's a proposal for syntax to help with this in JS, incidentally: https://github.com/tc39/proposal-explicit-resource-managemen...

There is no reason why you could not, in principle, have Rust-style compile-time borrow checking in a managed language.

As an extreme example (that I have occasionally thought about doing though probably won't), you could fork TypeScript and add ownership and lifetime and inherited-mutability annotations to it, and have the compiler enforce single-ownership and shared-xor-mutable except in code that has specifically opted out of this. As with existing features of TypeScript's type system, this wouldn't affect the emitted code at all—heap allocations would still be freed nondeterministically by the tracing GC at runtime, not necessarily at the particular point in the program where they stop being used—but you'd get the maintainability benefits of not allowing unrestricted aliasing.

(Since you wouldn't have destructors, you might need to use linear instead of affine types, to ensure that programmers can't forget to call a resource object's cleanup method when they're done with it. Alternatively, you could require https://github.com/tc39/proposal-explicit-resource-managemen... to be used, once that gets added to JavaScript.)

Of course, if you design a runtime specifically to be targeted by such a language, more becomes possible. See https://without.boats/blog/revisiting-a-smaller-rust/ for one sketch of what this might look like.

Things like https://github.com/tc39/proposal-explicit-resource-managemen.... Essentially better language level support for objects which represent some IO resource that should be reliably closed when a user is done with it. Something like the `defer` statement in Go is really missing from JS.

I would like to mention maud in this context:

https://github.com/lambda-fairy/maud

It is refreshingly different from other Rust templating libraries. It uses a proc-macro that compiles your HTML into Rust code. I also happen to use it in conjunction with HTMX and it works very well for me (at least in small projects).

You can also use HTML templating with crates like askama, tera and maud! This can be combined with the power of lightweight JavaScript libraries like htmx to speed up time to production. You can read more about this on our other article about using HTMX with Rust which you can find here.. We also collaborated with Stefan Baumgartner on an article for serving HTML with Askama!

I think a lot of us reach for Jinja-style templates so it feels a little more like we're writing bare HTML. But they're of course still just templates, and they need a build step before they become valid HTML.

So it's true, if you're willing to use a DSL embedded in your server language (like JSX), then you'll have the full language tooling available to you. And this probably isn't giving up much over language-specific templates.

A JSX-equivalent for the Rust server-side rendering world would probably be maud [1] or leptops [2].

[1] https://github.com/lambda-fairy/maud

[2] https://github.com/leptos-rs/leptos

Maud as a performant templating engine that will ensure your templates are well-formed at compile-time and, in effect, minify the generated HTML output by not passing through unnecessary whitespace.

Maud is a fast Slim/Haml-esque templating engine which will automatically minify your HTML at no extra charge because whitespace isn't significant in its syntax.

If you want to do backend development, give actix-web or Axum a try. If you need templating, take a look at Maud and if you want an ORM, take a look at SeaORM.

Personally, I'd recommend Maud if you don't need something with runtime reloading. Not only is it much faster, it implements a template language that is effectively the Rust-syntax equivalent to Slim or Haml using a procedural macro, so you get compile-time verification that your HTML output is well-formed.

For templating, Maud is fast, gives compile-time well-formedness guarantees, and outputs minified HTML by default as a side-effect of it being based on Rust macros. (It's of a similar design philosophy to Slim and Haml)